Search

Your search keyword '"Photometric"' showing total 178 results
Start Over Descriptor "Photometric" Topic techniques
178 results on '"Photometric"'

1. First light simultaneous triple-channel optical observations of the OPTICAM system at the OAN-SPM.

Author

Castro, Angel, Michel, Raúl, Castro Segura, Noel, Altamirano, Diego, Tejada, Carlos, Herrera, Joel, Colorado, Enrique, Sierra, Gerardo, Altamirano-Dévora, Liliana, Echevarría, Juan, Sloot, Rasjied, Wijnands, Rudy, Zavala, Iván, Rojas, David, Hernández Santisteban, Juan V., Vincentelli, Federico, Hernández-Landa, Javier A., Wang, Song, Fuentes, Melissa, and Gandhi, Poshak

Subjects
*SCIENTIFIC apparatus & instruments, *ASTRONOMICAL observatories, *ASTRONOMICAL observations, *SCIENTIFIC observation, *OBSERVATORIES
Abstract

OPTICAM is a triple-band optical system developed for the 2.1 m telescope of the National Astronomical Observatory in the Sierra de San Pedro Mártir (OAN-SPM). Partial engineering tests were conducted in 2019, with the complete system experiencing its first light in March 2022. The system incorporates two beam splitters, enabling simultaneous observations on three channels. Users can choose three out of the five available filters from the SDSS filter set ( u ′ g ′ r ′ i ′ z ′ ), covering the wavelength range from 320 to 1000 nm. It offers an effective field of view of approximately 4.7, 4.7, and 5.6 arcminutes in each of its arms, respectively. Due to its design and capabilities, OPTICAM is suitable for coordinated observations with other ground-based and space-based observatories. This document presents the final instrument design and the current system status. Some of the optical tests carried out are described. We also present the results of scientific observations conducted during its first light and first year of operations. • First triple-channel optical astronomical observations with OPTICAM. • Description of the optomechanical design and instrument testing. • The technical and scientific capabilities of the instrument are discussed. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

3. WASP-18b Secondary Eclipses Revisited Using TESS Observation.

Author

Eftekhar, M.

Subjects
*MARKOV chain Monte Carlo, *RANDOM noise theory, *GAUSSIAN processes, *HOT Jupiters, *LIGHT curves, *ECLIPSES
Abstract

We report the characterization of a transiting hot Jupiter WASP-18b at optical wavelengths measured by the transiting exoplanet survey satellite (TESS). We analyze the publicly available data collected by the TESS in sector 2. Here, we model the systematic noise using Gaussian processes (GPs) and fit it to the data using the Markov Chain Monte Carlo (MCMC) method. Modelling the TESS light curve returns a planet-to-star radius ratio, p = 0.098010 − 0.000346 + 0.000368 and secondary eclipse depth of 354 − 10 + 11 part-per-million (ppm). The transit ephemeris of WASP-18b is updated using the MCMC method. Finally, we use updated ephemeris to look for transit time variations (TTVs) for WASP-18b to complement our study. We find a quite small deviation of transit timings from a linear ephemeris, which is statistically insignificant. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

4. The New Ephemeris and Light Curve Analysis of V870 Ara by the Ground-Based and TESS Data

Author

Poro Atila, Blackford Mark G., Davoudi Fatemeh, Mohandes Amirreza, Madani Mohammad, Rezaei Samaneh, and Bozorgzadeh Elnaz

Subjects
techniques, photometric, binaries, eclipsing, stars, individual (v870 ara), Astronomy, QB1-991
Abstract

New CCD photometric observations and their investigation of the W UMa-type binary, V870 Ara, are presented. Light curves of the system were taken through BVIfilters from the Congarinni Observatory in Australia. The new ephemeris is calculated based on seven new determined minimum times, together with the TESS data and others compiled from the literature. Photometric solutions determined by the Wilson-Devinney (W-D) code are combined with the Monte Carlo simulation to determine the adjustable parameters’ uncertainties. These solutions suggest that V870 Ara is a contact binary system with a mass ratio of 0.082, a fillout factor of 96±4 percent, and an inclination of 73.60±0.64 degrees. The absolute parameters of V870 Ara were determined by combining the Gaia EDR3 parallax and photometric elements.

Published
2021
Full Text
View/download PDF

5. QHY-174M-GPS CAMERA AS THE DEVICE FOR PHOTOMETRY OF ARTIFICIAL SATELLITES.

Author

Kudak, Viktor and Perig, Vasyl

Subjects
*ARTIFICIAL satellites, *PHOTOMETRY, *METEORS, *CAMERAS, *LIGHT curves
Abstract

In this paper, we make an attempt to use the QHY174M-GPS camera for the photometry research of fast-rotating artificial objects including debris, satellites and rocket bodies. This device is useful for imaging occultations, eclipses, meteors, and so on due to a highly precise recording of the time (GPS-based) and location of the observation on every frame and fast readout of the CMOS detector. The precision of time registration by the QHY174M-GPS camera is at the level of microseconds. All light curves obtained by studied camera during observations of artificial satellites in this work were carried out at Derenivka Observatory of Uzhhorod National University, Ukraine. The created photometric system with QHY174M-GPS camera as the detector and reflector telescope with parameters D=120 mm, F=114 mm, FOV=2.82°-1.76° was calibrated. For target observations, SharpCap software was used. For the purposes of photometry processing, ccd_phot software was developed using Python 3.8 programming language with astropy and photutils packages. Photometry observations of artificial satellites of the Earth and standard stars were carried out. Over 80 lightcurves of artificial satellites were obtained. Comparing synchronous observations from two sites, separated 15 km from each other, we can conclude that photometry on the QHY174M-GPS camera gave us the same shape of lightcurve and additional advantages, such as time of exposure or simplicity of usage. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

6. A Comprehensive Comparison of Period Extraction Algorithms for Asteroids with Long Term Observation.

Author

Yang Liu, Liming Wu, Tianqi Sun, Pengfei Zhang, Xi Fang, Liyun Cheng, and Bin Jiang

Subjects
*ASTEROIDS, *LIGHT curves, *DATA analysis, *PHOTOMETRY, *DATABASES
Abstract

The light curve period of an asteroid plays an important role in determining the rotation period, the collision evolution and the YORP effect. There are many period extraction algorithms used to find the light curve period of asteroids with long term observation, which are mainly based on the frequency, time and time--frequency domains. This paper presents a comprehensive and unparalleled comparison of the popular algorithms based on the DAMIT (Database of Asteroid Models from Inversion Techniques) data set to show the statistical results. Considering the quoted period, absolute magnitude, diameter, albedo, time span and number of observations, we analyze the accuracy of five popular methods using the light curve data of 2902 asteroids. We find that although the performance of all the algorithms varies little, Phase Dispersion Minimization (PDM) performs better, followed by Lomb-Scargle (LS), while Conditional Entropy (CE) is not better than the others under certain conditions. We also analyze the cases which are more suitable for searching by frequencies or by periods. [ABSTRACT FROM AUTHOR]

Published
2021
Full Text
View/download PDF

7. A critical assessment of ages derived using pre-main-sequence isochrones in colour-magnitude diagrams

Author

Bell, Cameron Pearce MacDonald and Tim, Naylor

Subjects
523.88, stars, evolution, stars, formation, stars, pre-main-sequence, techniques, photometric, open clusters and associations, general, Hertzsprung-Russell and colour-magnitude diagrams
Abstract

In this thesis a critical assessment of the ages derived using theoretical pre-main-sequence (pre-MS) stellar evolutionary models is presented by comparing the predictions to the low-mass pre-MS population of 14 young star-forming regions (SFRs) in colour-magnitude diagrams (CMDs). Deriving pre-MS ages requires precise distances and estimates of the reddening. Therefore, the main-sequence (MS) members of the SFRs have been used to derive a self-consistent set of statistically robust ages, distances and reddenings with associated uncertainties using a maximum-likelihood fitting statistic and MS evolutionary models. A photometric method (known as the Q-method) for de-reddening individual stars in regions where the extinction is spatially variable has been updated and is presented. The effects of both the model dependency and the SFR composition on these derived parameters are also discussed. The problem of calibrating photometric observations of red pre-MS stars is examined and it is shown that using observations of MS stars to transform the data into a standard photometric system can introduce significant errors in the position of the pre-MS locus in CMD space. Hence, it is crucial that precise photometric studies (especially of pre- MS objects) be carried out in the natural photometric system of the observations. This therefore requires a robust model of the system responses for the instrument used, and thus the calculated responses for the Wide-Field Camera on the Isaac Newton Telescope are presented. These system responses have been tested using standard star observations and have been shown to be a good representation of the photometric system. A benchmark test for the pre-MS evolutionary models is performed by comparing them to a set of well-calibrated CMDs of the Pleiades in the wavelength regime 0.4−2.5 μm. The masses predicted by these models are also tested against dynamical masses using a sample of MS binaries by calculating the system magnitude in a given photometric band- pass. This analysis shows that for Teff ≤ 4000 K the models systematically overestimate the flux by a factor of 2 at 0.5 μm, though this decreases with wavelength, becoming negligible at 2.2 μm. Thus before the pre-MS models are used to derive ages, a recalibration of the models is performed by incorporating an empirical colour-Teff relation and bolometric corrections based on the Ks-band luminosity of Pleiades members, with theoretical corrections for the dependence on the surface gravity (log g). The recalibrated pre-MS model isochrones are used to derive ages from the pre-MS populations of the SFRs. These ages are then compared with the MS derivations, thus providing a powerful diagnostic tool with which to discriminate between the different pre- MS age scales that arise from a much stronger model dependency in the pre-MS regime. The revised ages assigned to each of the 14 SFRs are up to a factor two older than previous derivations, a result with wide-ranging implications, including that circumstellar discs survive longer and that the average Class II lifetime is greater than currently believed.

Published
2012

8. The optical and NIR luminous energy output of the Universe : the creation and utilisation of a 9 waveband consistent sample of galaxies using UKIDSS and SDSS observations with the GAMA and MGC spectroscopic datasets

Author

Hill, David T. and Driver, Simon Peter

Subjects
520, Galaxies, fundamental parameters, Surveys, Techniques, photometric, Methods, observational, Methods, data analysis, Techniques, imageprocessing, Galaxies, luminosity function, mass function, Galaxies, statistics, Galaxies, structure, Infrared, galaxies, QB857.5S87H5, Galaxies--Observation, Surveys, Surface brightness (Astronomy), Stars--Luminosity function, Galaxies--Evolution
Abstract

Theories of how galaxies form and evolve depend greatly on constraints provided by observations. However, when those observations come from different datasets, systematic offsets may occur. This causes difficulties measuring variations in parameters between filters. In this thesis I present the variation in total luminosity density with wavelength in the nearby Universe (z<0.1), produced from a consistent reanalysis of NIR and optical observations, taken from the MGC, UKIDSS and SDSS surveys. I derive luminosity distributions, best-fitting Schechter function parameterisations and total luminosity densities in ugrizYJHK, and compare the variation in luminosity density with cosmic star formation history (CSFH) and initial mass function (IMF) models. I examine the r band luminosity distribution produced using different aperture definitions, the joint luminosity- surface brightness (bivariate brightness) distribution in ugrizYJHK, comparing them to previously derived distributions, and how the total luminosity density varies with wavelength when surface brightness incompleteness is accounted for. I find the following results. (1) The total luminosity density calculated using a non-Sersic (e.g. Kron or Petrosian) aperture is underestimated by at least 15%, (2) Changing the detection threshold has a minor effect on the best-fitting Schecter parameters, but the choice of Kron or Petrosian apertures causes an offset between datasets, regardless of the filter used to define the source list, (3) The decision to use circular or elliptical apertures causes an offset in M* of 0.20 mag, and best-fitting Schechter parameters from total magnitude photometric systems have a flatter faint-end slope than Kron or Petrosian photometry, (4) There is no surface brightness distribution evolution with luminosity for luminous galaxies, but at fainter magnitudes the distribution broadens and the peak surface brightness dims. A Choloniewski function that is modified to account for this surface brightness evolution fits the bivariate-brightness distribution better than an unmodified Choloniewski function, (5) The energy density per unit interval, vf(v) derived using MGC and GAMA samples agrees within 90% confidence intervals, but does not agree with predictions using standard CSFH and IMF models. Possible improvements to the data and alterations to the theory are suggested.

Published
2011

9. Pulsating components of the eclipsing binaries with long period eccentric orbits.

Author

Yoldaş, Ezgi, Dal, Hasan Ali, and Özdarcan, Orkun

Subjects
*ECLIPSING binaries, *ORBITS (Astronomy), *LIGHT curves
Abstract

Taking into account the results found by analysing the Kepler data together with our photometric observations, we present new findings about KIC 5217733 and KIC 11671429, which are two highly eccentric detached eclipsing binaries. We estimate that the radii of the primary and secondary components should be, respectively, 5.41 ± 0.07 R ⊙ and 1.59 ± 0.07 R ⊙ , while their masses should be 2.59 ± 0.09 M ⊙ and 1.66 ± 0.09 M ⊙ for KIC 5217733, whose orbital period is 161.252379 days. In the case of KIC 11671429, whose orbital period is 112.463712 days, the radii of the primary and secondary components are estimated as 3.05 ± 0.07 R ⊙ and 1.60 ± 0.11 R ⊙ , and their masses are computed as 1.64 ± 0.09 M ⊙ and 1.52 ± 0.14 M ⊙ , respectively. The frequency analyses of the variations at out-of-eclipses reveal that both targets exhibit pulsations. In these pulsations, the g - m o d e s are dominant for KIC 521773, while the p - m o d e s are dominant for KIC 11671429. • We analyzed the eccentric light curves of KIC 5217733 and KIC 11671429. • The variations seen out of eclipses in the light curves were investigated. • The primary components are evolved, secondaries are located in the Instability Strip. • 1323 frequencies are detected for KIC 5217733 and 400 frequencies for KIC 11671429. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

10. A super-Earth and a mini-Neptune near the 2:1 MMR straddling the radius valley around the nearby mid-M dwarf TOI-2096

Author

F. J. Pozuelos, M. Timmermans, B. V. Rackham, L. J. Garcia, A. J. Burgasser, S. R. Kane, M. N. Günther, K. G. Stassun, V. Van Grootel, M. Dévora-Pajares, R. Luque, B. Edwards, P. Niraula, N. Schanche, R. D. Wells, E. Ducrot, S. Howell, D. Sebastian, K. Barkaoui, W. Waalkes, C. Cadieux, R. Doyon, R. P. Boyle, J. Dietrich, A. Burdanov, L. Delrez, B.-O. Demory, J. de Wit, G. Dransfield, M. Gillon, Y. Gómez Maqueo Chew, M. J. Hooton, E. Jehin, C. A. Murray, P. P. Pedersen, D. Queloz, S. J. Thompson, A. H. M. J. Triaud, S. Zúñiga-Fernández, K. A. Collins, M. M Fausnaugh, C. Hedges, K. M. Hesse, J. M. Jenkins, M. Kunimoto, D. W. Latham, A. Shporer, E. B. Ting, G. Torres, P. Amado, J. R. Rodón, C. Rodríguez-López, J. C. Suárez, R. Alonso, Z. Benkhaldoun, Z. K. Berta-Thompson, P. Chinchilla, M. Ghachoui, M. A. Gómez-Muñoz, R. Rebolo, L. Sabin, U. Schroffenegger, E. Furlan, C. Gnilka, K. Lester, N. Scott, C. Aganze, R. Gerasimov, C. Hsu, C. Theissen, D. Apai, W. P. Chen, P. Gabor, T. Henning, and L. Mancini

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), stars, TOI-2096, planets and satellites, Settore FIS/05, FOS: Physical sciences, Astronomy and Astrophysics, techniques, photometric, low-mass, individual, Space and Planetary Science, Astrophysics - Earth and Planetary Astrophysics
Abstract

Several planetary formation models have been proposed to explain the observed abundance and variety of compositions of super-Earths and mini-Neptunes. In this context, multitransiting systems orbiting low-mass stars whose planets are close to the radius valley are benchmark systems, which help to elucidate which formation model dominates. We report the discovery, validation, and initial characterization of one such system, TOI-2096, composed of a super-Earth and a mini-Neptune hosted by a mid-type M dwarf located 48 pc away. We first characterized the host star by combining different methods. Then, we derived the planetary properties by modeling the photometric data from TESS and ground-based facilities. We used archival data, high-resolution imaging, and statistical validation to support our planetary interpretation. We found that TOI-2096 corresponds to a dwarf star of spectral type M4. It harbors a super-Earth (R$\sim1.2 R_{\oplus}$) and a mini-Neptune (R$\sim1.90 R_{\oplus}$) in likely slightly eccentric orbits with orbital periods of 3.12 d and 6.39 d, respectively. These orbital periods are close to the first-order 2:1 mean-motion resonance (MMR), which may lead to measurable transit timing variations (TTVs). We computed the expected TTVs amplitude for each planet and found that they might be measurable with high-precision photometry delivering mid-transit times with accuracies of $\lesssim$2 min. Moreover, measuring the planetary masses via radial velocities (RVs) is also possible. Lastly, we found that these planets are among the best in their class to conduct atmospheric studies using the James Webb Space Telescope (JWST). The properties of this system make it a suitable candidate for further studies, particularly for mass determination using RVs and/or TTVs, decreasing the scarcity of systems that can be used to test planetary formation models around low-mass stars., 25 pages, 21 figures. Aceptted for publication in Astronomy & Astrophysics

Published
2023

11. Photometric binaries, mass functions, and structural parameters of 78 Galactic open clusters

Author

Giacomo Cordoni, Antonino P. Milone, Anna F. Marino, Enrico Vesperini, Emanuele Dondoglio, Maria Vittoria Legnardi, Anjana Mohandasan, Marilia Carlos, Edoardo P. Lagioia, Sohee Jang, and Tuila Ziliotto

Subjects
stars, open clusters and associations, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, photometric, techniques, binaries, close, Hertzsprung-Russell and C-M diagrams, luminosity function, mass function, general, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

Binary stars play a crucial role in our understanding of the formation and evolution of star clusters and their stellar populations. We use Gaia Data Release 3 to homogeneously analyze 78 Galactic open clusters and the unresolved binary systems they host, each composed of two main sequence (MS) stars. We first investigated the structural parameters of these clusters, such as the core radius and the central density, and determined the cluster mass function (MF) and total mass by interpolating the density profile of each cluster. We measured the fraction of binaries with a large mass ratio and the fraction of blue straggler stars (BSSs), and finally investigated possible connections between the populations of binary stars and BSSs with the main parameters of the host cluster. {Remarkably, we find that the MFs of 78 analyzed open clusters follow a similar trend and are well reproduced by two single power-law functions, with a change in slope around masses of 1$M_{\odot}$. The fraction of binary stars ranges from $\sim$15\% to more than $\sim$60\% without significant correlation with the mass and the age of the host cluster. Moreover, we detect hints of a correlation between the total fraction of binary stars and the central density of the host cluster. We compared the fraction of binary stars with that of BSSs, finding that clusters with high and low central density exhibit different trends. The fraction of binaries does not significantly change with the mass of the primary star and the mass ratio. The radial distribution of binary stars depends on cluster age. The binaries of clusters younger than $\sim$800\,Myr typically show a flat radial distribution, with some hints of a double peak. In contrast, the binaries of the remaining clusters are more centrally concentrated than the single stars, which is similar to what is observed in globular clusters., Comment: 27 pages, 27 figures, accepted for publication in Astronomy & Astrophysics

Published
2023
Full Text
View/download PDF

12. Analysis of ground-based observations of some exoplanets.

Author

Püsküllü, Çağlar and Soydugan, Faruk

Subjects
*EXTRASOLAR planets, *ASTRONOMICAL transits, *ASTRONOMICAL observatories, *PLANETARY observations, *PLANETARY systems
Abstract

We present analyses of the transit light curves and transit time measurements of the exoplanets HAT-P-3b, HD 189733b, and WASP-43b. Transit light curves were collected at Çanakkale Onsekiz Mart University Observatory and TÜBİTAK National Observatory. The models were produced by WINFITTER code and stellar, planetary, and orbital properties were obtained and discussed. We searched for significant signals at the O-C diagrams generated with our transit times and additional data based on Exoplanet Transit Database. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

13. Physical properties of the trans-Neptunian object (38628) Huya from a multi-chord stellar occultation

Author

P. Santos-Sanz, J. L. Ortiz, B. Sicardy, M. Popescu, G. Benedetti-Rossi, N. Morales, M. Vara-Lubiano, J. I. B. Camargo, C. L. Pereira, F. L. Rommel, M. Assafin, J. Desmars, F. Braga-Ribas, R. Duffard, J. Marques Oliveira, R. Vieira-Martins, E. Fernández-Valenzuela, B. E. Morgado, M. Acar, S. Anghel, E. Atalay, A. Ateş, H. Bakiş, V. Bakis, Z. Eker, O. Erece, S. Kaspi, C. Kayhan, S. E. Kilic, Y. Kilic, I. Manulis, D. A. Nedelcu, M. S. Niaei, G. Nir, E. Ofek, T. Ozisik, E. Petrescu, O. Satir, A. Solmaz, A. Sonka, M. Tekes, O. Unsalan, C. Yesilyaprak, R. Anghel, D. Berteşteanu, L. Curelaru, C. Danescu, V. Dumitrescu, R. Gherase, L. Hudin, A-M. Stoian, J. O. Tercu, R. Truta, V. Turcu, C. Vantdevara, I. Belskaya, T. O. Dementiev, K. Gazeas, S. Karampotsiou, V. Kashuba, Cs. Kiss, N. Koshkin, O. M. Kozhukhov, Y. Krugly, J. Lecacheux, A. Pal, Ç. Püsküllü, R. Szakats, V. Zhukov, D. Bamberger, B. Mondon, C. Perelló, A. Pratt, C. Schnabel, A. Selva, J. P. Teng, K. Tigani, V. Tsamis, C. Weber, G. Wells, S. Kalkan, V. Kudak, A. Marciniak, W. Ogloza, T. Özdemir, E. Pakštiene, V. Perig, M. Żejmo, Ministerio de Ciencia e Innovación (España), European Commission, European Research Council, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Institut Polytechnique des Sciences Avancées (IPSA)

Subjects
Albedo, Kuiper belt objects, FOS: Physical sciences, Density, Huya, methods, photometric, Size, Methods: observational, individual: huya, methods: observational, techniques: photometric, astrophysics - earth and planetary astrophysics, astrophysics - solar and stellar astrophysics [kuiper belt objects], observational, individual, Variability, Solar and Stellar Astrophysics (astro-ph.SR), Earth and Planetary Astrophysics (astro-ph.EP), Ring, Pluto, Atmosphere, Kuiper belt objects: individual: Huya, Astronomy and Astrophysics, Bodies, Astrophysics - Solar and Stellar Astrophysics, [SDU]Sciences of the Universe [physics], Space and Planetary Science, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], techniques, Centaur, Orbit, Techniques: photometric, Astrophysics - Earth and Planetary Astrophysics
Abstract

Full list of authors: Santos-Sanz, P.; Ortiz, J. L.; Sicardy, B.; Popescu, M.; Benedetti-Rossi, G.; Morales, N.; Vara-Lubiano, M.; Camargo, J. I. B.; Pereira, C. L.; Rommel, F. L.; Assafin, M.; Desmars, J.; Braga-Ribas, F.; Duffard, R.; Marques Oliveira, J.; Vieira-Martins, R.; Fernández-Valenzuela, E.; Morgado, B. E.; Acar, M.; Anghel, S.; Atalay, E.; Ateş, A.; Bakiş, H.; Bakis, V.; Eker, Z.; Erece, O.; Kaspi, S.; Kayhan, C.; Kilic, S. E.; Kilic, Y.; Manulis, I.; Nedelcu, D. A.; Niaei, M. S.; Nir, G.; Ofek, E.; Ozisik, T.; Petrescu, E.; Satir, O.; Solmaz, A.; Sonka, A.; Tekes, M.; Unsalan, O.; Yesilyaprak, C.; Anghel, R.; Berteşteanu, D.; Curelaru, L.; Danescu, C.; Dumitrescu, V.; Gherase, R.; Hudin, L.; Stoian, A. -M.; Tercu, J. O.; Truta, R.; Turcu, V.; Vantdevara, C.; Belskaya, I.; Dementiev, T. O.; Gazeas, K.; Karampotsiou, S.; Kashuba, V.; Kiss, Cs.; Koshkin, N.; Kozhukhov, O. M.; Krugly, Y.; Lecacheux, J.; Pal, A.; Püsküllü, Ç.; Szakats, R.; Zhukov, V.; Bamberger, D.; Mondon, B.; Perelló, C.; Pratt, A.; Schnabel, C.; Selva, A.; Teng, J. P.; Tigani, K.; Tsamis, V.; Weber, C.; Wells, G.; Kalkan, S.; Kudak, V.; Marciniak, A.; Ogloza, W.; Özdemir, T.; Pakštiene, E.; Perig, V.; Żejmo, M.--This is an Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited., Context. As part of our international program aimed at obtaining accurate physical properties of trans-Neptunian objects (TNOs), we predicted a stellar occultation by the TNO (38628) Huya of the star Gaia DR2 4352760586390566400 (mG = 11.5 mag) on March 18, 2019. After an extensive observational campaign geared at obtaining the astrometric data, we updated the prediction and found it favorable to central Europe. Therefore, we mobilized half a hundred of professional and amateur astronomers in this region and the occultation was finally detected by 21 telescopes located at 18 sites in Europe and Asia. This places the Huya event among the best ever observed stellar occultation by a TNO in terms of the number of chords. Aims. The aim of our work is to determine an accurate size, shape, and geometric albedo for the TNO (38628) Huya by using the observations obtained from a multi-chord stellar occultation. We also aim to provide constraints on the density and other internal properties of this TNO. Methods. The 21 positive detections of the occultation by Huya allowed us to obtain well-separated chords which permitted us to fit an ellipse for the limb of the body at the moment of the occultation (i.e., the instantaneous limb) with kilometric accuracy. Results. The projected semi-major and minor axes of the best ellipse fit obtained using the occultation data are (a′, b′) = (217.6 ± 3.5 km, 194.1 ± 6.1 km) with a position angle for the minor axis of P′ = 55.2° ± 9.1. From this fit, the projected area-equivalent diameter is 411.0 ± 7.3 km. This diameter is compatible with the equivalent diameter for Huya obtained from radiometric techniques (D = 406 ± 16 km). From this instantaneous limb, we obtained the geometric albedo for Huya (pV = 0.079 ± 0.004) and we explored possible three-dimensional shapes and constraints to the mass density for this TNO. We did not detect the satellite of Huya through this occultation, but the presence of rings or debris around Huya was constrained using the occultation data. We also derived an upper limit for a putative Pluto-like global atmosphere of about psurf = 10 nbar. © P. Santos-Sanz et al. 2022., P.S-S. acknowledges financial support by the Spanish grant AYA-RTI2018-098657-J-I00 “LEO-SBNAF” (MCIU/AEI/FEDER, UE). P.S-S., J.L.O., N.M., M.V-L. and R.D. acknowledge financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709), they also acknowledge the financial support by the Spanish grants AYA-2017-84637-R and PID2020-112789GB-I00, and the Proyectos de Excelencia de la Junta de Andalucía 2012-FQM1776 and PY20-01309. The research leading to these results has received funding from the European Union’s Horizon 2020 Research and Innovation Programme, under Grant Agreement no. 687378, as part of the project “Small Bodies Near and Far” (SBNAF). Part of the research leading to these results has received funding from the European Research Council under the European Community’s H2020 (2014-2020/ERC Grant Agreement no. 669416 “LUCKY STAR”). Part of the work of M.P. was financed by a grant of the Romanian National Authority for Scientific Research and Innovation, CNCS – UEFISCDI PN-III-P1-1.1-TE-2019-1504. This study was financed in part by the Coordenaçâo de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001 and the National Institute of Science and Technology of the e-Universe project (INCT do e-Universo, CNPq grant 465376/2014-2). The following authors acknowledge the respective CNPq grants: F.B-R 309578/2017-5; R.V.-M. 304544/2017-5, 401903/2016-8; J.I.B.C. 308150/2016-3 and 305917/2019-6; M.A 427700/2018-3, 310683/2017-3 and 473002/2013-2; B.E.M. 150612/2020-6. G.B.R. thanks the support of CAPES and FAPERJ/PAPDRJ (E26/203.173/2016) grant. J.M.O. acknowledges financial support from the Portuguese Foundation for Science and Technology (FCT) and the European Social Fund (ESF) through the PhD grant SFRH/BD/131700/2017. E.F-V. acknowledges funding through the Preeminant Postdoctoral Program of the University of Central Florida. C.K., A.P. and R.S. have been supported by the grants K-125015 and K-138962 of the National Research, Development and Innovation Office (NKFIH, Hungary). E.P. acknowledges the Europlanet 2024 RI project funded by the European Union’s Horizon 2020 Research and Innovation Programme (Grant agreement No. 871149). We are grateful to the CAHA and OSN staffs. This research is partially based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by Junta de Andalucía and Consejo Superior de Investigaciones Científicas (IAA-CSIC). This research was also partially based on observation carried out at the Observatorio de Sierra Nevada (OSN) operated by Instituto de Astrofísica de Andalucía (CSIC). This article is also based on observations made in the Observatorios de Canarias del IAC with the Liverpool Telescope operated on the island of La Palma by the Instituto de Astrofísica de Canarias in the Observatorio del Roque de los Muchachos. Part of the results were based on observations taken at Pico dos Dias Observatory of the National Laboratory of Astrophysics (LNA/Brazil). Part of the data were collected during the photometric monitoring observations with the robotic and remotely controlled observatory at the University of Athens Observatory – UOAO (Gazeas 2016). We thank the Adiyaman University Astrophysics Application and Research Center for their support in the acquisition of data with the ADYU60 telescope. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement.

Published
2022
Full Text
View/download PDF

14. High-precision multiwavelength eclipse photometry of the ultra-hot gas giant exoplanetWASP-103 b.

Author

Delrez, L., Madhusudhan, N., Lendl, M., Gillon, M., Anderson, D. R., Neveu-VanMalle, M., Bouchy, F., Burdanov, A., Collier-Cameron, A., Demory, B. O., Hellier, C., Jehin, E., Magain, P., Maxted, P. F. L., Queloz, D., Smalley, B., and Triaud, A. H. M. J.

Subjects
*LIGHT curves, *ASTRONOMICAL spectroscopy, *OCCULTATIONS (Astronomy), *SPHERICAL astronomy, *LIGHT transmission, *JUPITER (Planet)
Abstract

We present 16 occultation and three transit light curves for the ultra-short period hot Jupiter WASP-103b, in addition to five new radial velocity measurements. We combine these observations with archival data and perform a global analysis of the resulting extensive data set, accounting for the contamination from a nearby star. We detect the thermal emission of the planet in both the ɀ' and KS bands, the measured occultation depths being 699±110 ppm (6.4σ) and 3567+400--350 ppm (10.2σ), respectively.We use these two measurements, together with recently published HST/WFC3 data, to derive joint constraints on the properties of WASP- 103b's dayside atmosphere. On one hand, we find that the ɀ' band and WFC3 data are best fit by an isothermal atmosphere at 2900K or an atmosphere with a low H2O abundance. On the other hand, we find an unexpected excess in the KS band measured flux compared to these models, which requires confirmation with additional observations before any interpretation can be given. From our global data analysis, we also derive a broad-band optical transmission spectrum that shows a minimum around 700 nm and increasing values towards both shorter and longer wavelengths. This is in agreement with a previous study based on a large fraction of the archival transit light curves used in our analysis. The unusual profile of this transmission spectrum is poorly matched by theoretical spectra and is not confirmed by more recent observations at higher spectral resolution. Additional data, in both emission and transmission, are required to better constrain the atmospheric properties of WASP-103b. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

15. VaST: A variability search toolkit.

Author

Sokolovsky, K.V. and Lebedev, A.A.

Subjects
ASTRONOMICAL photometry, USER interfaces, COMPUTERS in astronomy, LIGHT curves of variable stars, COMPUTER software
Abstract

Variability Search Toolkit (VaST) is a software package designed to find variable objects in a series of sky images. It can be run from a script or interactively using its graphical interface. VaST relies on source list matching as opposed to image subtraction. SExtractor is used to generate source lists and perform aperture or PSF-fitting photometry (with PSFEx). Variability indices that characterize scatter and smoothness of a lightcurve are computed for all objects. Candidate variables are identified as objects having high variability index values compared to other objects of similar brightness. The two distinguishing features of VaST are its ability to perform accurate aperture photometry of images obtained with non-linear detectors and handle complex image distortions. The software has been successfully applied to images obtained with telescopes ranging from 0.08 to 2.5 m in diameter equipped with a variety of detectors including CCD, CMOS, MIC and photographic plates. About 1800 variable stars have been discovered with VaST. It is used as a transient detection engine in the New Milky Way (NMW) nova patrol. The code is written in C and can be easily compiled on the majority of UNIX-like systems. VaST is free software available at http://scan.sai.msu.ru/vast/ . [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

16. The masses of retired A stars with asteroseismology: Kepler and K2 observations of exoplanet hosts.

Author

North, Thomas S. H., Campante, Tiago L., Andxsrea Miglio, Andxsrea, Davies, Guy R., Grunblatt, Samuel K., Huber, Daniel, Kuszlewicz, James S., Lund, Mikkel N., Cooke, Benjamin F., and Chaplin, William J.

Subjects
*ASTEROSEISMOLOGY, *ASTEROID detection, *STELLAR luminosity function, *RADIAL velocity of stars, *A stars, *STELLAR mass
Abstract

We investigate the masses of 'retired A stars' using asteroseismic detections on seven lowluminosity red-giant and sub-giant stars observed by the NASA Kepler and K2 missions. Our aim is to explore whether masses derived from spectroscopy and isochrone fitting may have been systematically overestimated. Our targets have all previously been subject to longterm radial velocity observations to detect orbiting bodies, and satisfy the criteria used by Johnson et al. to select survey stars which may have had A-type (or early F-type) mainsequence progenitors. The sample actually spans a somewhat wider range in mass, from ≈1 M☉ up to ≈1.7 M☉. Whilst for five of the seven stars the reported discovery mass from spectroscopy exceeds the mass estimated using asteroseismology, there is no strong evidence for a significant, systematic bias across the sample. Moreover, comparisons with other masses from the literature show that the absolute scale of any differences is highly sensitive to the chosen reference literature mass, with the scatter between different literature masses significantly larger than reported error bars. We find that any mass difference can be explained through use of different constraints during the recovery process. We also conclude that underestimated uncertainties on the input parameters can significantly bias the recovered stellar masses, which may have contributed to the controversy on the mass scale for retired A stars. [ABSTRACT FROM AUTHOR]

Published
2017
Full Text
View/download PDF

17. An analysis of the BVRI colors of 22 active comets.

Author

Betzler, A.S., Almeida, R.S., Cerqueira, W.J., Araujo, L.A., Prazeres, C.J.M., Jesus, J.N., Bispo, P.A.S., Andrade, V.B., Freitas, Y.A.S., and Betzler, L.B.S.

Subjects
*COMETS spectra, *COMETS, *COLOR index (Astronomy), *SOLAR system, *COMET photographic measurements, *EQUIPMENT & supplies
Abstract

Our aim was to analyze the variation of Johnson-Kron-Cousins BVRI color indexes of a sample with 22 active comets of various dynamic groups with the time, geometrical, observational and dynamical parameters. We performed photometric observations of 16 comets between 2010 and 2014, using robotic telescopes in three continents. In addition to the sample, we used data of six comets available in the literature. A statistical comparison between the distributions of color indexes was performed using the Kruskal-Wallis H-test. The color indexes of active comets can vary a few tenths up to a magnitude on time scales that range from hours to weeks. Using the B–V colors of the observed comets, we generated a relationship that correlates the cometary visual and CCD magnitudes. We did not identify any relationship between B–V and V–R colors with heliocentric distance and phase angle. The color B–V is correlated with the photometric aperture that can be described by a logarithmic function. We did not identify any differences in the distribution of B–V color among the comets analyzed at a confidence level equal to or greater than 95%. The mean color of active comets are B–R = 1.20 ± 0.24 , B–V = 0.76 ± 0.16 and V–R = 0.42 ± 0.16 . Active comets with V–R colors outside the three standard deviation interval can be considered objects with unusual physical characteristics. [ABSTRACT FROM AUTHOR]

Published
2017
Full Text
View/download PDF

18. Multiscale entropy analysis of astronomical time series. Discovering subclusters of hybrid pulsators

Author

Andrew Tkachenko and Jeroen Audenaert

Subjects
GAMMA DORADUS STARS, data analysis, KEPLER, FOS: Physical sciences, asteroseismology, Astronomy & Astrophysics, methods, photometric, VARIABLE-STARS, Astrophysics::Solar and Stellar Astrophysics, observational, PERIOD SPACINGS, Instrumentation and Methods for Astrophysics (astro-ph.IM), Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, STELLAR VARIABILITY, Science & Technology, SOLAR-TYPE, Astronomy and Astrophysics, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Physical Sciences, AUTOMATED CLASSIFICATION, DELTA-SCUTI, techniques, Astrophysics - Instrumentation and Methods for Astrophysics, statistical, METHODOLOGY
Abstract

The multiscale entropy assesses the complexity of a signal across different timescales. It originates from the biomedical domain and was recently successfully used to characterize light curves as part of a supervised machine learning framework to classify stellar variability. We explore the behavior of the multiscale entropy in detail by studying its algorithmic properties in a stellar variability context and by linking it with traditional astronomical time series analysis methods. We subsequently use the multiscale entropy as the basis for an interpretable clustering framework that can distinguish hybrid pulsators with both p- and g-modes from stars with only p-mode pulsations, such as $\delta$ Sct stars, or from stars with only g-mode pulsations, such as $\gamma$ Dor stars. We find that the multiscale entropy is a powerful tool for capturing variability patterns in stellar light curves. The multiscale entropy provides insights into the pulsation structure of a star and reveals how short- and long-term variability interact with each other based on time-domain information only. We also show that the multiscale entropy is correlated to the frequency content of a stellar signal and in particular to the near-core rotation rates of g-mode pulsators. We find that our new clustering framework can successfully identify the hybrid pulsators with both p- and g-modes in sets of $\delta$ Sct and $\gamma$ Dor stars, respectively. The benefit of our clustering framework is that it is unsupervised. It therefore does not require previously labeled data and hence is not biased by previous knowledge., Comment: 14 pages, 15 figures, 2 tables, Accepted for publication in Astronomy & Astrophysics

Published
2022

19. A warm super-Neptune around the G-dwarf star TOI-1710 revealed with TESS, SOPHIE and HARPS-N

Author

P.-C. König, M. Damasso, G. Hébrard, L. Naponiello, P. Cortés-Zuleta, K. Biazzo, N. C. Santos, A. S. Bonomo, A. Lecavelier des Étangs, L. Zeng, S. Hoyer, A. Sozzetti, L. Affer, J. M. Almenara, S. Benatti, A. Bieryla, I. Boisse, X. Bonfils, W. Boschin, A. Carmona, R. Claudi, K. A. Collins, S. Dalal, M. Deleuil, X. Delfosse, O. D. S. Demangeon, S. Desidera, R. F. Díaz, T. Forveille, N. Heidari, G. A. J. Hussain, J. Jenkins, F. Kiefer, G. Lacedelli, D. W. Latham, L. Malavolta, L. Mancini, E. Martioli, G. Micela, P. A. Miles-Páez, C. Moutou, D. Nardiello, V. Nascimbeni, M. Pinamonti, G. Piotto, G. Ricker, R. P. Schwarz, S. Seager, R. G. Stognone, P. A. Strøm, R. Vanderspek, J. Winn, J. Wittrock, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Settore FIS/05, activity, star: activity, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, spectroscopic, photometric, planetary systems, techniques: photometric, techniques: spectroscopic, techniques: radial velocities, star, [SDU]Sciences of the Universe [physics], Space and Planetary Science, techniques, radial velocities, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the discovery and characterization of the transiting extrasolar planet TOI-1710$\:$b. It was first identified as a promising candidate by the Transiting Exoplanet Survey Satellite (TESS). Its planetary nature was then established with SOPHIE and HARPS-N spectroscopic observations via the radial-velocity method. The stellar parameters for the host star are derived from the spectra and a joint Markov chain Monte-Carlo (MCMC) adjustment of the spectral energy distribution and evolutionary tracks of TOI-1710. A joint MCMC analysis of the TESS light curve and the radial-velocity evolution allows us to determine the planetary system properties. From our analysis, TOI-1710$\:$b is found to be a massive warm super-Neptune ($M_{\rm p}=28.3\:\pm\:4.7\:{\rm M}_{\rm Earth}$ and $R_{\rm p}=5.34\:\pm\:0.11\:{\rm R}_{\rm Earth}$) orbiting a G5V dwarf star ($T_{\rm eff}=5665\pm~55\mathrm{K}$) on a nearly circular 24.3-day orbit ($e=0.16\:\pm\:0.08$). The orbital period of this planet is close to the estimated rotation period of its host star $P_{\rm rot}=22.5\pm2.0~\mathrm{days}$ and it has a low Keplerian semi-amplitude $K=6.4\pm1.0~\mathrm{m\:s^{-1}}$; we thus performed additional analyses to show the robustness of the retrieved planetary parameters. With a low bulk density of $1.03\pm0.23~\mathrm{g\:cm^{-3}}$ and orbiting a bright host star ($J=8.3$, $V=9.6$), TOI-1710$\:$b is one of the best targets in this mass-radius range (near the Neptunian desert) for atmospheric characterization via transmission spectroscopy, a key measurement in constraining planet formation and evolutionary models of sub-Jovian planets., 18 pages, 16 figures, 5 tables, A&A in press

Published
2022
Full Text
View/download PDF

20. A New Approach to the Long-Term Activity Behavior of DM UMa

Author

Taş G. and Evren S.

Subjects
techniques, photometric, stars, late, type, activity, starspots, individual, dm uma, Astronomy, QB1-991
Abstract

A long-term activity character of DM UMa (K0-1 IV-III), which is one of the most active members of the RS CVn type variables, is examined using the multicolor photometric observations which spread to the time interval between 1980 and 2009. In this work, we present a new approximation for the long-term light and color variation of DM UMa using data obtained by combining our own observations obtained in the Johnson broad-band U,B,V,R filters between the years 1997 and 2008 and data published in literature. Available light and color data were examined for the long-term and seasonal variations using PERIOD04 program. The period analysis of the V-band data reveals the period estimations of 51.2±2.8 years and 15.1±0.7 years superposed on it. The U-B, B-V and V-R colors do not show correlation with the longer period, but they show variations with a period similar to the shorter one, except for B-V color. The amplitude variation also does not exhibit any correlation with the V light and color curves. It is found that the movement of the spot minima phases in years also indicates the migration period of nearly 15 years, similar to the period derived from the analysis of the long-term photometric observations in V-band.

Published
2012
Full Text
View/download PDF

21. Symbiotic Nova PU Vul - 33 Years of Observations

Author

Shugarov S., Chochol D., and Kolotilov E.

Subjects
stars, binaries, symbiotic, novae, eclipsing, agb, techniques, photometric, Astronomy, QB1-991
Abstract

We present UBVRI light curves of the symbiotic nova PU Vul after its outburst in 1978. Three observed eclipses of the hot component by the cool one were used to determine the ephemeris of the binary system as JD (Min I) = 2444550(15) + 4897(10) × E days. the 194-day shift of the secondary minimum from its expected positions in 2001 suggests the eccentricity of the binary orbit. Period analysis of the VRI photometry improved the pulsation period of the cool AGB variable in the system to P = 217.7 days. Pulsation of the cool component is detected only in the phases around the primary minimum, when the visible hemisphere of the AGB star is not influenced by the interaction with the hot component.

Published
2012
Full Text
View/download PDF

22. The BIMA Project: Two Years Report and Analysis of O-C Diagram on V566 Oph.

Author

Ramadhan, Dhimaz G., Haans, Gabriela K., Azaliah, Rhisa, Irawati, Puji, Akhyar, Saeful, Sarotsakulchai, Thawicharat, Arifin, Zainuddin M., Suherli, Janette, Malasan, Hakim L., Richichi, Andrea, and Soonthornthum, Boonrucksar

Subjects
*ECLIPSING binaries, *BINARY stars, *ASTRONOMICAL observations, *ASTRONOMICAL observatories, *MULTIPLE stars
Abstract

The Eclipsing Binaries' Minima Monitoring Project (BIMA) is a joint project between Institut Teknologi Bandung (ITB) and National Astronomical Research Institute of Thailand (NARIT). This project is dedicated to observe minim of eclipsing binaries light curves to derived their time of minimum. Since its commissioning in 2012, this project has secured 71 minima of more than 30 eclipising binaries until September 2014. In the first year, BIMA project has established the observational technique, data handling system, calculation for determination time of minimum, and automatization for image reduction and analysis. In the second year, BIMA project began to combine its time of minimum data with other previous observations to analyze O-C (Observed-Calculated) Diagram of all observed systems. The O-C diagram is one of indispensable tools to study evolution in eclipsing binaries in which it indicates period change or correction for periode prediction. Period changes closely related to evolutionary phase of the systems can be detected. In this paper, we present and discuss preliminary analysis of O-C diagram from one particular eclipsing binary system, V566 Oph. [ABSTRACT FROM AUTHOR]

Published
2015
Full Text
View/download PDF

23. Homogeneous transit timing analyses of 10 exoplanet systems

Author

Ö Baştürk, E M Esmer, S Yalçınkaya, Ş Torun, L Mancini, F Helweh, E Karamanlı, J Southworth, S Aliş, A Wünsche, F Tezcan, Y Aladağ, N Aksaker, E Tunç, F Davoudi, S Fişek, M Bretton, D F Evans, C Yeşilyaprak, M Yılmaz, C T Tezcan, K Yelkenci, Helweh, Fadel El, Karamanlı, Ertuğrul, and Tunç, Ege

Subjects
Hat-P-32, Wasp-103, Orbits, Individual, methods: observational, techniques: photometric, planetary systems, stars: individual: HAT-P-23, WASP-37, WASP-69, WASP-74, HAT-P-56, WASP-2, WASP-14, HAT-P-32, WASP-103, HAT-P-37, Hat-P-56, Photometric, Hat-P-37, Timing circuits, Methods, Observational, Wasp-14, Wasp-37, Settore FIS/05, Wasp-74, Astronomy and Astrophysics, Wasp-2, Geometrical optics, Stars, Techniques, Planetary systems, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Hat-p-23, Wasp-69
Abstract

We study the transit timings of 10 exoplanets in order to investigate potential transit timing variations in them. We model their available ground-based light curves, some presented here and others taken from the literature, and homogeneously measure the mid-transit times. We statistically compare our results with published values and find that the measurement errors agree. However, in terms of recovering the possible frequencies, homogeneous sets can be found to be more useful, of which no statistically relevant example has been found for the planets in our study. We corrected the ephemeris information of all 10 planets we studied and provide these most precise light elements as references for future transit observations with space-borne and ground-based instruments. We found no evidence for secular or periodic changes in the orbital periods of the planets in our sample, including the ultra-short period WASP-103 b, whose orbit is expected to decay on an observable time-scale. Therefore, we derive the lower limits for the reduced tidal quality factors (Q$^{\prime }_{\star }$) for the host stars based on best-fitting quadratic functions to their timing data. We also present a global model of all available data for WASP-74 b, which has a Gaia parallax-based distance value ∼25 per cent larger than the published value.

Published
2022

24. Constraining the overcontact phase in massive binary evolution -- II. Period stability of known O+O overcontact systems

Author

Michael Abdul-Masih, Ana Escorza, Athira Menon, Laurent Mahy, and Pablo Marchant

Subjects
stars, Science & Technology, STELLAR MERGERS, GRAVITATIONAL LENSING EXPERIMENT, BLUE STRAGGLERS, CHEMICALLY HOMOGENEOUS EVOLUTION, FOS: Physical sciences, Astronomy and Astrophysics, Astronomy & Astrophysics, CLOSE BINARIES, photometric, massive, ECLIPSING BINARIES, Astrophysics - Solar and Stellar Astrophysics, VARIABLE-STARS, Space and Planetary Science, Physical Sciences, evolution, SKY AUTOMATED SURVEY, CONTACT BINARIES, close, binaries, techniques, Solar and Stellar Astrophysics (astro-ph.SR), BLACK-HOLE MERGERS
Abstract

Given that mergers are often invoked to explain many exotic phenomena in massive star evolution, understanding the evolutionary phase directly preceding a merger, the overcontact phase, is of crucial importance. Despite its importance, large uncertainties exist in our understanding of the evolution of massive overcontact binaries. We aim to provide robust observational constraints on the future dynamical evolution of massive overcontact systems by measuring the rate at which the periods change for a sample of six such objects. Furthermore, we aim to investigate whether the periods of unequal mass systems show higher rates of change than their equal mass counterparts as theoretical models predict. Using archival photometric data from various ground- and space-based missions covering up to ~40 years, we measure the periods of each system over several smaller time spans. We then fit a linear regression through the measured periods to determine the rate at which the period is changing over the entire data set. We find that all of the stars in our sample have very small period changes and that there does not seem to be a correlation with the mass ratio. This implies that the orbital periods for these systems are stable on the nuclear timescale, and that the unequal mass systems may not equalize as expected. When comparing our results with population synthesis distributions, we find large discrepancies between the expected mass ratios and period stabilities. We find that these discrepancies can be mitigated to a degree by removing systems with shorter initial periods, suggesting that the observed sample of overcontact systems may originate from binary systems with longer initial orbital periods., Comment: 11 pages, 6 (+5) Figures, accepted for publication in A&A

Published
2022
Full Text
View/download PDF

25. The PAU Survey and Euclid: Improving broadband photometric redshifts with multi-task learning

Author

L. Cabayol, M. Eriksen, J. Carretero, R. Casas, F. J. Castander, E. Fernández, J. Garcia-Bellido, E. Gaztanaga, H. Hildebrandt, H. Hoekstra, B. Joachimi, R. Miquel, C. Padilla, A. Pocino, E. Sanchez, S. Serrano, I. Sevilla, M. Siudek, P. Tallada-Crespí, N. Aghanim, A. Amara, N. Auricchio, M. Baldi, R. Bender, D. Bonino, E. Branchini, M. Brescia, J. Brinchmann, S. Camera, V. Capobianco, C. Carbone, M. Castellano, S. Cavuoti, A. Cimatti, R. Cledassou, G. Congedo, C. J. Conselice, L. Conversi, Y. Copin, L. Corcione, F. Courbin, M. Cropper, A. Da Silva, H. Degaudenzi, M. Douspis, F. Dubath, C. A. J. Duncan, X. Dupac, S. Dusini, S. Farrens, P. Fosalba, M. Frailis, E. Franceschi, P. Franzetti, B. Garilli, W. Gillard, B. Gillis, C. Giocoli, A. Grazian, F. Grupp, S. V. H. Haugan, W. Holmes, F. Hormuth, A. Hornstrup, P. Hudelot, K. Jahnke, M. Kümmel, S. Kermiche, A. Kiessling, M. Kilbinger, R. Kohley, H. Kurki-Suonio, S. Ligori, P. B. Lilje, I. Lloro, E. Maiorano, O. Mansutti, O. Marggraf, K. Markovic, F. Marulli, R. Massey, S. Mei, M. Meneghetti, E. Merlin, G. Meylan, M. Moresco, L. Moscardini, E. Munari, R. Nakajima, S. M. Niemi, S. Paltani, F. Pasian, K. Pedersen, V. Pettorino, G. Polenta, M. Poncet, L. Popa, L. Pozzetti, F. Raison, R. Rebolo, J. Rhodes, G. Riccio, C. Rosset, E. Rossetti, R. Saglia, B. Sartoris, P. Schneider, A. Secroun, G. Seidel, C. Sirignano, G. Sirri, L. Stanco, A. N. Taylor, I. Tereno, R. Toledo-Moreo, F. Torradeflot, I. Tutusaus, E. Valentijn, L. Valenziano, Y. Wang, J. Weller, G. Zamorani, J. Zoubian, S. Andreon, V. Scottez, A. Tramacere, UAM. Departamento de Física Teórica, Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Centre National d'Études Spatiales [Toulouse] (CNES), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Euclid, HEP, INSPIRE, Department of Physics, and Helsinki Institute of Physics

Subjects
data analysis, surveys, methods, techniques, image processing, photometric, observational, Surveys, Methods: Data Analysis, Techniques: Image Processing, Methods: Observational, image processing [Techniques], observational [Methods], [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], data analysis [Methods], photometric [Techniques], Techniques: Photometric, Física, Astronomy and Astrophysics, 115 Astronomy, Space science, Astrophysics - Astrophysics of Galaxies, [PHYS.PHYS.PHYS-INS-DET] Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Space and Planetary Science, [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, los autores pertenecientes a la UAM y el nombre del grupo de colaboración, si lo hubiere, Current and future imaging surveys require photometric redshifts (photo-zs) to be estimated for millions of galaxies. Improving the photo-z quality is a major challenge but is needed to advance our understanding of cosmology. In this paper we explore how the synergies between narrow-band photometric data and large imaging surveys can be exploited to improve broadband photometric redshifts. We used a multi-task learning (MTL) network to improve broadband photo-z estimates by simultaneously predicting the broadband photo-z and the narrow-band photometry from the broadband photometry. The narrow-band photometry is only required in the training field, which also enables better photo-z predictions for the galaxies without narrow-band photometry in the wide field. This technique was tested with data from the Physics of the Accelerating Universe Survey (PAUS) in the COSMOS field. We find that the method predicts photo-zs that are 13% more precise down to magnitude iAB < 23; the outlier rate is also 40% lower when compared to the baseline network. Furthermore, MTL reduces the photo-z bias for high-redshift galaxies, improving the redshift distributions for tomographic bins with z > 1. Applying this technique to deeper samples is crucial for future surveys such as Euclid or LSST. For simulated data, training on a sample with iAB < 23, the method reduces the photo-z scatter by 16% for all galaxies with iAB < 25. We also studied the effects of extending the training sample with photometric galaxies using PAUS high-precision photo-zs, which reduces the photo-z scatter by 20% in the COSMOS field, The PAU Survey is partially supported by MINECO under grants CSD2007-00060, AYA2015-71825, ESP2017-89838, PGC2018-094773, PGC2018-102021, SEV-2016-0588, SEV-2016-0597, MDM-2015-0509, PID2019-111317GB-C31 and Juan de la Cierva fellowship and LACEGAL and EWC Marie Sklodowska-Curie grant No 734374 and no.776247 with ERDF funds from the EU Horizon 2020 Programme, some of which include ERDF funds from the European Union. IEEC and IFAE are partially funded by the CERCA and Beatriu de Pinos program of the Generalitat de Catalunya. Funding for PAUS has also been provided by Durham University (via the ERC StG DEGAS-259586), ETH Zurich, Leiden University (via ERC StG ADULT279396 and Netherlands Organisation for Scientific Research (NWO) Vici grant 639.043.512), Bochum University (via a Heisenberg grant of the Deutsche Forschungsgemeinschaft (Hi 1495/5-1) as well as an ERC Consolidator Grant (No. 770935)), University College London, Portsmouth support through the Royal Society Wolfson fellowship and from the European Union’s Horizon 2020 research and innovation programme under the grant agreement No 776247 EWC. The results published were also funded by the Polish National Agency for Academic Exchange (Bekker grant BPN/BEK/2021/1/00298/DEC/1), the European Union’s Horizon 2020 research and innovation programme under the Maria Skłodowska-Curie (grant agreement No 754510) and by the Spanish Ministry of Science and Innovation through Juan de la Cierva-formacion program (reference FJC2018-038792-I)

Published
2023
Full Text
View/download PDF

26. Starspot signature on the light curve.

Author

Santos, A. R. G., Cunha, M. S., Avelino, P. P., García, R. A., and Mathur, S.

Subjects
*STARSPOTS, *LIGHT curves, *STELLAR rotation, *ASTRONOMICAL photometry, *SECOND harmonic generation
Abstract

Context. Quasi-periodic modulations of the stellar light curve may result from dark spots crossing the visible stellar disc. Owing to di erential rotation, spots at di erent latitudes generally have di erent rotation periods. Hence, by studying spot-induced modulations, it is possible to learn about stellar surface (di erential) rotation and magnetic activity. Recently, a method based on the Lomb-Scargle periodogram of light curves has been proposed to identify the sign of the di erential rotation at the stellar surface. Aims. Our goal is to understand how the modulation of the stellar light curve due to the presence of spots and the corresponding periodogram are a ected by both the stellar and spot properties. Methods. We generate synthetic light curves of stars with di erent properties (inclination angle, limb darkening, and rotation rate) and spot configurations (number of spots, latitude, intensity contrast, and size). By analysing their Lomb-Scargle periodograms, we compute the ratio between the heights of the second and first harmonics of the rotation period (peak-height ratio). Results. We find that the peak-height ratios are essentially a function of a single parameter, the fraction of time the spot is visible, which is related to the sinusoidality of the spot modulation. We identify the conditions under which the periodogram analysis can actually provide an estimate of the spot latitudes and/or the stellar inclination angle. We also identify possible sources of error in the identification of the sign of the di erential rotation. [ABSTRACT FROM AUTHOR]

Published
2017
Full Text
View/download PDF

27. A Comprehensive Comparison of Period Extraction Algorithms for Asteroids with Long Term Observation

Author

Pengfei Zhang, Liyun Cheng, Liming Wu, Bin Jiang, Yang Liu, Tianqi Sun, and Xi Fang

Subjects
Conditional entropy, Physics, Rotation period, asteroids, Phase dispersion minimization, data analysis, General Physics and Astronomy, Elementary particle physics, QC793-793.5, Albedo, Light curve, miscellaneous, Term (time), methods, Data set, photometric, Asteroid, general, astronomical databases, techniques, Algorithm
Abstract

The light curve period of an asteroid plays an important role in determining the rotation period, the collision evolution and the YORP effect. There are many period extraction algorithms used to find the light curve period of asteroids with long term observation, which are mainly based on the frequency, time and time–frequency domains. This paper presents a comprehensive and unparalleled comparison of the popular algorithms based on the DAMIT (Database of Asteroid Models from Inversion Techniques) data set to show the statistical results. Considering the quoted period, absolute magnitude, diameter, albedo, time span and number of observations, we analyze the accuracy of five popular methods using the light curve data of 2902 asteroids. We find that although the performance of all the algorithms varies little, Phase Dispersion Minimization (PDM) performs better, followed by Lomb-Scargle (LS), while Conditional Entropy (CE) is not better than the others under certain conditions. We also analyze the cases which are more suitable for searching by frequencies or by periods.

Published
2021

28. Euclid preparation. XII. Optimizing the photometric sample of the Euclid survey for galaxy clustering and galaxy-galaxy lensing analyses

Author

Martin Crocce, Chiara Sirignano, O. Mansutti, L. Whittaker, Massimo Meneghetti, I. Ferrero, Alina Kiessling, Edwin A. Valentijn, Gianluca Castignani, S. Maurogordato, Giuseppe Riccio, P. B. Lilje, Carlo Burigana, Rafael Toledo-Moreo, B. Gillis, Davide Maino, Felix Hormuth, G. Sirri, F. Sureau, W. A. Holmes, Marco Baldi, Richard Massey, Knud Jahnke, K. Pedersen, A. Da Silva, Enrico Bozzo, E. Romelli, Simona Mei, C. Bodendorf, Jussi Valiviita, L. Popa, R. Cledassou, Luigi Guzzo, Andrea Cimatti, A. Pocino, F. Raison, Hélène M. Courtois, M. Tenti, Jarle Brinchmann, Robert C. Nichol, M. Poncet, Massimo Brescia, D. Di Ferdinando, Ghassem Gozaliasl, G. Meylan, D. Bonino, C. Neissner, C. S. Carvalho, Anne Costille, C. A. J. Duncan, M. Viel, A. Balaguera-Antolínez, Valeria Pettorino, Leonardo Corcione, S. Serrano, X. Dupac, Jean Coupon, C. Baccigalupi, R. Benton Metcalf, S. Farrens, Lauro Moscardini, V. Scottez, Yu Wang, Marco Castellano, G. Zamorani, Roberto P. Saglia, Andrea Biviano, Martin Kunz, F. Grupp, S. Casas, S. M. Niemi, J. Nightingale, Enzo Branchini, A. Secroun, N. Martinet, Mark Cropper, G. Seidel, Ismael Tereno, L. Stanco, L. Conversi, E. Medinaceli, Doug Potter, Stefano Cavuoti, Lucia Pozzetti, A. Cappi, F. J. Castander, C. C. Kirkpatrick, G. Congedo, R. Nakajima, Emanuel Rossetti, B. Morin, Fabio Finelli, F. Lacasa, Y. Copin, C. Padilla, Andrea Tramacere, W. Gillard, M. Martinelli, E. Keihänen, S. Kermiche, Mauro Roncarelli, Domenico Sapone, B. Garilli, I. Lloro, E. Munari, Sotiria Fotopoulou, Ariel G. Sánchez, Julien Zoubian, T. Vassallo, Romain Teyssier, Stefano Camera, Ole Marggraf, S. de la Torre, Z. Sakr, V. Capobianco, L. Patrizii, Carlo Giocoli, Stefano Andreon, S. Dusini, M. Frailis, A. Balestra, Ralf Bender, Pedro G. Ferreira, A. Boucaud, Jason Rhodes, Luca Valenziano, E. Zucca, F. Dubath, S. Bardelli, G. Polenta, Pablo Fosalba, Peter Schneider, Elisabetta Maiorano, Fabio Pasian, Hannu Kurki-Suonio, Jean-Gabriel Cuby, N. Welikala, Natalia Auricchio, Thomas D. Kitching, A. Porredon, V. F. Cardone, C. Colodro-Conde, Michele Moresco, Andy Taylor, Will J. Percival, Alkistis Pourtsidou, Christopher J. Conselice, S. Paltani, E. Franceschi, Sebastiano Ligori, Roberto Scaramella, Javier Graciá-Carpio, A. Renzi, Remi A. Cabanac, S. Galeotta, S. Pires, Federico Marulli, Andrea Zacchei, I. Tutusaus, Astronomy, Pocino, A., Tutusaus, I., Castander, F. J., Fosalba, P., Crocce, M., Porredon, A., Camera, S., Cardone, V., Casas, S., Kitching, T., Lacasa, F., Martinelli, M., Pourtsidou, A., Sakr, Z., Andreon, S., Auricchio, N., Baccigalupi, C., Balaguera-Antolinez, A., Baldi, M., Balestra, A., Bardelli, S., Bender, R., Biviano, A., Bodendorf, C., Bonino, D., Boucaud, A., Bozzo, E., Branchini, E., Brescia, M., Brinchmann, J., Burigana, C., Cabanac, R., Capobianco, V., Cappi, A., Carvalho, C. S., Castellano, M., Castignani, G., Cavuoti, S., Cimatti, A., Cledassou, R., Colodro-Conde, C., Congedo, G., Conselice, C. J., Conversi, L., Copin, Y., Corcione, L., Costille, A., Coupon, J., Courtois, H. M., Cropper, M., Cuby, J. -G., Da Silva, A., De La Torre, S., Di Ferdinando, D., Dubath, F., Duncan, C., Dupac, X., Dusini, S., Farrens, S., Ferreira, P. G., Ferrero, I., Finelli, F., Fotopoulou, S., Frailis, M., Franceschi, E., Galeotta, S., Garilli, B., Gillard, W., Gillis, B., Giocoli, C., Gozaliasl, G., Gracia-Carpio, J., Grupp, F., Guzzo, L., Holmes, W., Hormuth, F., Jahnke, K., Keihanen, E., Kermiche, S., Kiessling, A., Kirkpatrick, C. C., Kunz, M., Kurki-Suonio, H., Ligori, S., Lilje, P. B., Lloro, I., Maino, D., Maiorano, E., Mansutti, O., Marggraf, O., Martinet, N., Marulli, F., Massey, R., Maurogordato, S., Medinaceli, E., Mei, S., Meneghetti, M., Benton Metcalf, R., Meylan, G., Moresco, M., Morin, B., Moscardini, L., Munari, E., Nakajima, R., Neissner, C., Nichol, R. C., Niemi, S., Nightingale, J., Padilla, C., Paltani, S., Pasian, F., Patrizii, L., Pedersen, K., Percival, W. J., Pettorino, V., Pires, S., Polenta, G., Poncet, M., Popa, L., Potter, D., Pozzetti, L., Raison, F., Renzi, A., Rhodes, J., Riccio, G., Romelli, E., Roncarelli, M., Rossetti, E., Saglia, R., Sanchez, A. G., Sapone, D., Scaramella, R., Schneider, P., Scottez, V., Secroun, A., Seidel, G., Serrano, S., Sirignano, C., Sirri, G., Stanco, L., Sureau, F., Taylor, A. N., Tenti, M., Tereno, I., Teyssier, R., Toledo-Moreo, R., Tramacere, A., Valentijn, E. A., Valenziano, L., Valiviita, J., Vassallo, T., Viel, M., Wang, Y., Welikala, N., Whittaker, L., Zacchei, A., Zamorani, G., Zoubian, J., Zucca, E., Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National d'Études Spatiales [Toulouse] (CNES), Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Euclid, Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Department of Physics, Research Program in Systems Oncology, Helsinki Institute of Physics, Pocino A., Tutusaus I., Castander F.J., Fosalba P., Crocce M., Porredon A., Camera S., Cardone V., Casas S., Kitching T., Lacasa F., Martinelli M., Pourtsidou A., Sakr Z., Andreon S., Auricchio N., Baccigalupi C., Balaguera-Antolinez A., Baldi M., Balestra A., Bardelli S., Bender R., Biviano A., Bodendorf C., Bonino D., Boucaud A., Bozzo E., Branchini E., Brescia M., Brinchmann J., Burigana C., Cabanac R., Capobianco V., Cappi A., Carvalho C.S., Castellano M., Castignani G., Cavuoti S., Cimatti A., Cledassou R., Colodro-Conde C., Congedo G., Conselice C.J., Conversi L., Copin Y., Corcione L., Costille A., Coupon J., Courtois H.M., Cropper M., Cuby J.-G., Da Silva A., De La Torre S., Di Ferdinando D., Dubath F., Duncan C., Dupac X., Dusini S., Farrens S., Ferreira P.G., Ferrero I., Finelli F., Fotopoulou S., Frailis M., Franceschi E., Galeotta S., Garilli B., Gillard W., Gillis B., Giocoli C., Gozaliasl G., Gracia-Carpio J., Grupp F., Guzzo L., Holmes W., Hormuth F., Jahnke K., Keihanen E., Kermiche S., Kiessling A., Kirkpatrick C.C., Kunz M., Kurki-Suonio H., Ligori S., Lilje P.B., Lloro I., Maino D., Maiorano E., Mansutti O., Marggraf O., Martinet N., Marulli F., Massey R., Maurogordato S., Medinaceli E., Mei S., Meneghetti M., Benton Metcalf R., Meylan G., Moresco M., Morin B., Moscardini L., Munari E., Nakajima R., Neissner C., Nichol R.C., Niemi S., Nightingale J., Padilla C., Paltani S., Pasian F., Patrizii L., Pedersen K., Percival W.J., Pettorino V., Pires S., Polenta G., Poncet M., Popa L., Potter D., Pozzetti L., Raison F., Renzi A., Rhodes J., Riccio G., Romelli E., Roncarelli M., Rossetti E., Saglia R., Sanchez A.G., Sapone D., Scaramella R., Schneider P., Scottez V., Secroun A., Seidel G., Serrano S., Sirignano C., Sirri G., Stanco L., Sureau F., Taylor A.N., Tenti M., Tereno I., Teyssier R., Toledo-Moreo R., Tramacere A., Valentijn E.A., Valenziano L., Valiviita J., Vassallo T., Viel M., Wang Y., Welikala N., Whittaker L., Zacchei A., Zamorani G., Zoubian J., and Zucca E.

Subjects
luminous red galaxies, Cosmological parameter, Astrophysics, Surveys, 01 natural sciences, Cosmology, techniques: photometric, galaxies, Galaxies: distances and redshift, distances and redshifts, Survey, 010303 astronomy & astrophysics, Weak gravitational lensing, Physics, Redshift survey, lsst, astro-ph.CO, galaxies: distances and redshifts, constraints, Astrophysics - Cosmology and Nongalactic Astrophysics, redshift survey, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Cosmological parameters, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, photometric, Settore FIS/05 - Astronomia e Astrofisica, surveys, 0103 physical sciences, distances and redshifts [Galaxies], cosmological parameters, Spurious relationship, Cluster analysis, dark energy survey, Astrophysics::Galaxy Astrophysics, 010308 nuclear & particles physics, photometric [Techniques], Astronomy and Astrophysics, space, 115 Astronomy, Space science, Redshift, Galaxy, Space and Planetary Science, Galaxies: distances and redshifts, Techniques: photometric, techniques, Focus (optics), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], cosmology, cosmic shear, intrinsic alignments
Abstract

Pocino, A., et al. (Euclid Collaboration), Photometric redshifts (photo-zs) are one of the main ingredients in the analysis of cosmological probes. Their accuracy particularly affects the results of the analyses of galaxy clustering with photometrically selected galaxies (GCph) and weak lensing. In the next decade, space missions such as Euclid will collect precise and accurate photometric measurements for millions of galaxies. These data should be complemented with upcoming ground-based observations to derive precise and accurate photo-zs. In this article we explore how the tomographic redshift binning and depth of ground-based observations will affect the cosmological constraints expected from the Euclid mission. We focus on GCph and extend the study to include galaxy-galaxy lensing (GGL). We add a layer of complexity to the analysis by simulating several realistic photo-z distributions based on the Euclid Consortium Flagship simulation and using a machine learning photo-z algorithm. We then use the Fisher matrix formalism together with these galaxy samples to study the cosmological constraining power as a function of redshift binning, survey depth, and photo-z accuracy. We find that bins with an equal width in redshift provide a higher figure of merit (FoM) than equipopulated bins and that increasing the number of redshift bins from ten to 13 improves the FoM by 35% and 15% for GCph and its combination with GGL, respectively. For GCph, an increase in the survey depth provides a higher FoM. However, when we include faint galaxies beyond the limit of the spectroscopic training data, the resulting FoM decreases because of the spurious photo-zs. When combining GCph and GGL, the number density of the sample, which is set by the survey depth, is the main factor driving the variations in the FoM. Adding galaxies at faint magnitudes and high redshift increases the FoM, even when they are beyond the spectroscopic limit, since the number density increase compensates for the photo-z degradation in this case. We conclude that there is more information that can be extracted beyond the nominal ten tomographic redshift bins of Euclid and that we should be cautious when adding faint galaxies into our sample since they can degrade the cosmological constraints.

Published
2021
Full Text
View/download PDF

29. Transit analysis of the exoplanet host Kepler-485.

Author

Püsküllü, Çağlar and Soydugan, Faruk

Subjects
*DETECTION of extrasolar planets, *ASTRONOMICAL transits, *EXTRASOLAR planetary orbits
Abstract

In this study, we present solutions of the transit light curves of the recently discovered exoplanet Kepler-485b observed by the Kepler space telescope. To obtain stellar, planetary, and orbital properties, WINFITTER code was applied to transit light curve data, which are available at the NASA Exoplanet Archive (NEA). [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

30. Principles and Applications of the Synchronous Network of Remote Telescopes

Author

Zhilyaev B. E., Romanyuk Ya. O., Svyatogorov O. A., and Verlyuk I. A.

Subjects
techniques, photometric, methods, statistical, stars, variable, Astronomy, QB1-991
Abstract

A new approach for the search of microvariability and high-speed phenomena in variable stars is presented. It gives a new technology of observation and analysis of the data. Statistical photometry stands on the three pillars: the digital filtering technique, the photon counting statistics based on the Mandel equation, and the integral transforms of the light curves. This technique permits to investigate low-amplitude and rapid variability of stars.

Published
2003
Full Text
View/download PDF

31. Classification of Metal-Deficient Dwarfs in the Vilnius Photometric System

Author

Lazauskaitė R., Bartkevičius A., and Bartašiūtė S.

Subjects
techniques, photometric, stars, fundamental parameters (classification), population ii, Astronomy, QB1-991
Abstract

Methods used for the quantitative classification of metal-deficient stars in the Vilnius photometric system are reviewed. We present a new calibration of absolute magnitudes for dwarfs and subdwarfs, based on Hipparcos parallaxes. The new classification scheme is applied to a sample of Population II visual binaries.

Published
2003
Full Text
View/download PDF

33. Interstellar Extinction in the Gaia Photometric Systems

Author

Bridžius A. and Vansevičius V.

Subjects
techniques, photometric, stars, fundamental parameters, interstellar extinction, gaia orbiting observatory, Astronomy, QB1-991
Abstract

Three medium-band photometric systems proposed for the Gaia space mission are intercompared in determining color excesses for stars of spectral classes from O to M at V = 18 mag. A possibility of obtaining a three-dimensional map of the interstellar extinction is discussed.

Published
2003
Full Text
View/download PDF

34. Stellar Photometry at the Crossroads of the Two Centuries

Author

Straižys V.

Subjects
methods, observationa, techniques, photometric, stars, classification, physical parameters, interstellar reddening, Astronomy, QB1-991
Abstract

In the last century photometry was recognized as a powerful method for investigation of physical parameters of stars and of interstellar matter. Photometric investigations now cover the spectral range from the far ultraviolet to the far infrared. The article describes the most important landmarks in development of photometric classification of stars and the number of photometric survey projects accomplished by ground-based and space telescopes and including millions of point sources. The success of the future LSSD and Gaia projects will depend on the use of optimum photometric passbands.

Published
2003
Full Text
View/download PDF

35. Fast CCD Photometry in the Taiwan-America Occultation Survey

Author

Chen W. P., Zhang Z. W., King S. K., Alcock C., Byun Y. I., Cook K. H., Dave R., Giammarco J., Lee T., Lehner M., Liang C., Lissauer J., Marshall S., Pater I. de, Porrata R., Rice J., Wang A., Wang S. Y., and Wen C. Y.

Subjects
solar system, kuiper belt objects, methods, observational, techniques, photometric, Astronomy, QB1-991
Abstract

We describe the efforts of the Taiwan-America Occultation Survey (TAOS) project to develop a data acquisition and analysis scheme for fast CCD imaging photometry. The TAOS project aims to conduct a census of the Kuiper-belt objects (KBOs) by detecting chance stellar occultation events by these small bodies in the outer reach of the solar system. An array of telescopes, each with fast optics (f/2) of 0.5 m aperture and equipped with a 2K CCD camera (3 square degrees FOV), have been set up in central Taiwan to monitor a couple thousand stars simultaneously. By reading out the CCD chip sequentially a few rows of pixels at a time (pause-and-shift), it is possible to achieve stellar photometry with a sampling rate up to several hertz. Here we report how such a setup has been used to observe the SX Phoenicis type variable CY Aqr to illustrate the potential usefulness of the TAOS database in stellar variability studies.

Published
2003
Full Text
View/download PDF

36. Selecting a Photometric System for Gaia: C, N, O and Alpha-Process Elements

Author

Tautvaišienė G., Edvardsson B., and Bartašiūtė S.

Subjects
techniques, photometric, stars, abundances, orbiting observatories, gaia, Astronomy, QB1-991
Abstract

The sensitivity of stellar spectra to C, N, O and α-process element abundances is discussed with the aim of taking this effect into account when selecting a photometric system for the Gaia orbiting observatory. On the basis of a spectrometric, photometric and theoretical study of spectra of evolved first-ascent giants and clump stars in the open cluster NGC 7789 it is demonstrated that evolutionary alterations of carbon and nitrogen abundances can cause noticeable spectral changes and, if not taken into account, may yield misleading photometric [Fe/H] determinations. Carbon features in stellar atmospheres show a particularly complex behavior being dependent on mixing processes in stars, on the stellar surface gravity and on the abundance of oxygen which can also be altered by different reasons. NH bands could serve for the evaluation of mixing processes in stars and the interpretation of carbon dominated spectral regions. Abundances of α-process elements can be evaluated photometrically by using the direct indicators - Ca II H and K lines and Mg I b triplet.

Published
2003
Full Text
View/download PDF

37. The Reduction of CCD Images for Stellar Photometry on the Vatt

Author

Janusz R., Boyle R. P., and Philip A. G. Davis

Subjects
techniques, photometric, ccd photometry, reductions, Astronomy, QB1-991
Abstract

We briefly describe a method of organizing all the star field exposures taken in a complete CCD observational run. By a “CommandLog” (to be published in J. Astron. Data) one can organize all the observations and process them within IRAF in an orderly, automated manner to arrive at stellar photometry calibrated into a standard photometric system (in our case, Strömvil). During the course of this processing we determine the error of the flat and try to correct it.

Published
2003
Full Text
View/download PDF

38. On the Data Reduction of WET Observations

Author

Pakštienė Erika

Subjects
methods, data analysis, atmospheric effects, techniques, photometric, wet, Astronomy, QB1-991
Abstract

It is demonstrated how the length of a continuous time-series of photometric data and their gaps affect the power spectrum of a Fourier Transform of the data. It is shown that second order effects of the atmospheric extinction - the dependence of the extinction coefficient on spectral type of a star and on the air mass - cannot be ignored. The ignoring of these effects results in aliases at frequencies lower than 200 μHz. A modification of the extinction correction procedure is proposed.

Published
2003
Full Text
View/download PDF

39. On a New Technique for Discovering Variable Stars

Author

Mironov A. V., Zakharov A. I., and Nikolaev F. N.

Subjects
techniques, photometric, stars, variables, general, orbiting observatories, hipparcos, Astronomy, QB1-991
Abstract

A technique for discovering variable stars based on the calculation of the correlation coefficients is proposed. Applications of the technique are shown on the results of numerical experiments and on the Hipparcos photometric data.

Published
2003
Full Text
View/download PDF

40. Variations of the Ratio of Total-To-selective Extinction in the Galaxy

Author

Sūdžius J. and Raudeliūnas S.

Subjects
ism,dust, extinction, galaxy, structure, techniques, photometric, Astronomy, QB1-991
Abstract

The results of the study of variations of total-to-selective extinction RV near the Galactic plane (-12° ≤ b ≤+12°) are presented. It is shown that variations of RV range from 1.9 to 3.4 and it is not possible to determine its typical value for the Galaxy. The conclusion that variations of the parameter RV closely correlates with the distribution of interstellar extinction is confirmed.

Published
2003
Full Text
View/download PDF

41. Correction of UBV Photometry for Emission Lines

Author

Skopal A.

Subjects
techniques, photometric, stars, emission line, binaries, symbiotic, Astronomy, QB1-991
Abstract

We investigate the effect on U,B,V magnitudes of the removal of emission lines from the spectra of some symbiotic stars and novae during their nebular phases. We approach this problem by the precise reconstruction of the composite UV/optical continuum and the line spectrum. The corrections ΔU, ΔB and ΔV are determined from the ratio of fluxes with and without emission lines. We demonstrate the effect for symbiotic nova V1016 Cyg during its nebular phase. We find that about 68%, 78% and 66% of the observed flux in the U, B and V filters is radiated in the emission lines. The effect should be taken into account before using the observed color indices of emission-line objects for diagnosis of their radiation in the continuum.

Published
2003
Full Text
View/download PDF

42. Overlapping Open Clusters NGC 1750 and NGC 1758 behind the Taurus Dark Clouds. II. CCD Photometry in the Vilnius System

Author

Straižys V., Kazlauskas A., Černiauskas A., Boyle R. P., Vrba F. J., Philip A. G. Davis, Laugalys V., Černis K., and Smriglio F.

Subjects
techniques, photometric, vilnius photometric system stars, fundamental parameters, classification ism, extinction, dust clouds open clusters, individual objects, ngc 1750, ngc 1758, Astronomy, QB1-991
Abstract

Seven-color photometry in the Vilnius system has been obtained for 420 stars down to V = 16 mag in the area containing the overlapping open clusters NGC 1750 and NGC 1758 in Taurus. Spectral and luminosity classes, color excesses, interstellar extinctions and distances are given for 287 stars. The classification of stars is based on their reddening-free Q-parameters. 18 stars observed photoelectrically were used as standards. The extinction vs. distance diagram exhibits the presence of one dust cloud at a distance of 175 pc which almost coincides with a distance of other dust clouds in the Taurus complex. The clusters NGC 1750 and NGC 1758 are found to be at the same distance of ~760 pc and may penetrate each other. Their interstellar extinction AV is 1.06 mag which corresponds to EB-V = 0.34 mag.

Published
2003
Full Text
View/download PDF

43. Interstellar Extinction in the Direction of The Barnard 1 Dark Cloud in Perseus

Author

Černis K. and Straižys V.

Subjects
techniques, photometric, vilnius photometric system-stars, fundamental parameters, classification ism, extinction, dust clouds ism, individual objects, barnard 1, Astronomy, QB1-991
Abstract

Spectral and luminosity classes, absolute magnitudes, color excesses, interstellar extinctions and distances are determined for 98 stars down to 18 mag in the Barnard 1 dark cloud belonging to the Per OB2 association. The classification of stars is based on their photoelectric photometry in the Vilnius seven-color photometric system. The extinction vs. distance diagram exhibits the presence of two dust layers at 150 and 230 pc distances. The distance of the first cloud, which gives an extinction Ay of 0.3 mag, coincides with the distance of the Taurus dark cloud complex. The second cloud with much larger extinction is about at the same distance as the clouds in the direction of the nearby objects: reflection nebula NGC 1333 and open cluster IG 348.

Published
2003
Full Text
View/download PDF

44. Photoelectric Vilnius Photometry of Stars in the Mega Proper Motion Field KA 10

Author

Bartašiutė S.

Subjects
techniques, photometric, vilnius photometric system stars, fundamental parameters interstellar medium, extinction galaxy, solar neighborhood, Astronomy, QB1-991
Abstract

Photoelectric seven-color photometry in the Vilnius medium-band, system is obtained for 87 stars down to V≃13.0 in the Kiev proper motion field KA10 [l = 137°, b = -59°]. The size of the field is 1.4 square degrees. For each star, photometric spectral type, absolute magnitude, metallicity, and color excess due to interstellar reddening have been determined. These data, together with previous Vilnius photometry obtained in other seven KA fields at high Galactic latitudes, will be combined with radial-velocity measurements and available proper motions to yield space velocities and to investigate kinematical and chemical properties of the Galactic disk in the direction perpendicular to the Galactic plane.

Published
2003
Full Text
View/download PDF

45. Merging Data from Large and Small Telescopes – Good or Bad? And: How Useful is the Application of Statistical Weights to Time-Series Photometric Measurements?

Author

Handler G.

Subjects
techniques, photometric, Astronomy, QB1-991
Abstract

I have investigated the value of the contribution of small telescopes to the success of a whole WET run. To this end, I have applied different data weighting schemes to two extreme WET test data sets. I find that weights proportional to the inverse local scatter in the light curves produce Fourier Transforms of best signal-to-noise. Weighting data stronger than their inverse scatter does not yield optimal results because of the reduction of the effective number of data points.

Published
2003
Full Text
View/download PDF

46. TRIPP: An Aperture Photometry Package for the Reduction of CCD Time Series Images

Author

Schuh S. L., Dreizler S., Deetjen J. L., and Göhler E.

Subjects
techniques, image processing techniques, photometric, Astronomy, QB1-991
Abstract

TRIPP is an aperture photometry program designed with the purpose of extracting light curves from large sets of similar CCD frames typically obtained during time-resolved photometric monitoring campaigns such as, for example, WET runs. We describe its properties and usage with an emphasis on where the functionality of TRIPP may differ from similar programs, and try to outline both its strengths as well as the non-trivial issues where difficulties may arise.

Published
2003
Full Text
View/download PDF

47. Combining Aperture and PSF-Fitting Photometry

Author

Handler G.

Subjects
techniques, photometric, Astronomy, QB1-991
Abstract

The multiple object and multiple frame (MOMF) CCD photometry package, that combines the advantages of aperture and PSF photometry is described. Results from comparisons with other programs are given; no other photometry package was found to give better results than MOMF.

Published
2003
Full Text
View/download PDF

48. Telescope and Researcher Potential of Turkey for Collaboration in CV Studies

Author

Saygac A. Talat and Alis Sinan

Subjects
stars, novae, cataclysmic variables, telescopes, techniques, photometric, spectroscopic, Astronomy, QB1-991
Abstract

Turkish astronomical community has witnessed the construction of several telescopes in the last 10 years. These telescopes and the potential of young researchers in the country motivated this poster presentation which aims to receive attention for collaboration in the field of cataclysmic variables and related objects.

Published
2012
Full Text
View/download PDF

49. Exploiting timing capabilities of the CHEOPS mission with warm-Jupiter planets

Author

M. Steller, Magali Deleuil, Roberto Ragazzoni, G. Scandariato, Nascimbeni, J. Asquier, László L. Kiss, Yann Alibert, C. Broeg, Nuno C. Santos, David Barrado, Enric Palle, Damien Ségransan, Andrea Fortier, Don Pollacco, Monika Lendl, B.-O. Demory, T. G. Wilson, Demetrio Magrin, Giampaolo Piotto, Nicola Rando, T. Bandy, M. Fridlund, J. Hasiba, Michaël Gillon, Van Grootel, J. Cabrera, David Ehrenreich, Anders Erikson, Alexis Brandeker, Willy Benz, K. G. Isaak, N. A. Walton, I. Pagano, Jacques Laskar, E. Kopp, G. Escude, G. Olofsson, Z. Garai, Olivier Demangeon, C. Lovis, Pierre F. L. Maxted, Wolfgang Baumjohann, S. C. C. Barros, Nicolas Billot, Kevin Heng, Manuel Guedel, Sébastien Charnoz, Thomas Beck, T. Bárczy, Xavier Bonfils, Gyula M. Szabó, Szilard Csizmadia, A L des Etangs, Alexis M. S. Smith, Matteo Munari, L. Delrez, A. E. Simon, G. Lacedelli, L. Borsato, Sérgio F. Sousa, Didier Queloz, F. Marzari, Davide Gandolfi, L M Serrano, N. Thomas, Andrew Collier Cameron, Roi Alonso, Ignasi Ribas, Stéphane Udry, M. Beck, Sergio Hoyer, A. Bonfanti, Melvyn B. Davies, Heike Rauer, Luca Fossati, Gisbert Peter, Roland Ottensamer, Department of Brain and Behavioural Sciences, University of Pavia, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Instituto de RadioAstronomía Milimétrica (IRAM), Centre National de la Recherche Scientifique (CNRS), Keele University [Keele], Instituto de Astrofísica e Ciências do Espaço (IASTRO), Institut für Festkörper- und Materialphysik, Technische Universität Dresden, Technische Universität Dresden = Dresden University of Technology (TU Dresden), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science, Agenzia Spaziale Italiana, Hungarian Scientific Research Fund, Fundação para a Ciência e a Tecnologia (Portugal), and European Commission

Subjects
WASP-106 b, WASP-38b, Q1, 01 natural sciences, Jupiter, Planets and satellites: individual: HAT-P-17 b, KELT-6 b, WASP-8 b, WASP-38 b, WASP-106 b, WASP-130 b, K2-287 b, Techniques: photometric, techniques: photometric, HAT-P-17 b, Planet, QB460, QB Astronomy, Transit (astronomy), 010303 astronomy & astrophysics, QC, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, 520 Astronomy, Sampling (statistics), Planets and Satellites, 3rd-DAS, Exoplanet, Astrophysics::Earth and Planetary Astrophysics, FOS: Physical sciences, Individual, individual: HAT-P-17 b, KELT-6 b, WASP-8 b, WASP-38 b, WASP-106 b, WASP-130 b, K2-287 b [Planets and satellites], planets and satellites: individual: HAT-P-17 b, KELT-6 b, Photometric, 0103 physical sciences, WASP-8 b, QB600, 010308 nuclear & particles physics, photometric [Techniques], Astronomy, Astronomy and Astrophysics, WASP-130 b, Planetary system, 620 Engineering, Light curve, Techniques, QC Physics, K2-287 b, Space and Planetary Science, individual: HAT-P-17 b [Planets and satellites], WASP-38 b, Satellite, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics, QB799
Abstract

We present 17 transit light curves of seven known warm-Jupiters observed with the CHaracterising ExOPlanet Satellite (CHEOPS). The light curves have been collected as part of the CHEOPS Guaranteed Time Observation (GTO) program that searches for transit-timing variation (TTV) of warm-Jupiters induced by a possible external perturber to shed light on the evolution path of such planetary systems. We describe the CHEOPS observation process, from the planning to the data analysis. In this work, we focused on the timing performance of CHEOPS, the impact of the sampling of the transit phases, and the improvement we can obtain by combining multiple transits together. We reached the highest precision on the transit time of about 13-16 s for the brightest target (WASP-38, G = 9.2) in our sample. From the combined analysis of multiple transits of fainter targets with G ≥ 11, we obtained a timing precision of ∼2 min. Additional observations with CHEOPS, covering a longer temporal baseline, will further improve the precision on the transit times and will allow us to detect possible TTV signals induced by an external perturber., The early support for CHEOPS by Daniel Neuenschwander is gratefully acknowledged. GPi, VN, GSs, IPa, LBo, GLa, and RRa acknowledge the funding support from Italian Space Agency (ASI) regulated by ‘Accordo ASI-INAF n. 2013-016-R.0 del 9 luglio 2013 e integrazione del 9 luglio 2015 CHEOPS Fasi A/B/C’. GLa acknowledges support by CARIPARO Foundation, according to the agreement CARIPARO-Università degli Studi di Padova (Pratica n. 2018/0098), and scholarship support by the ‘Soroptimist International d’Italia’ association (Cortina d’Ampezzo Club). VVG is an FRS-FNRS Research Associate. VVG, LD, and MG thank the Belgian Federal Science Policy Office (BELSPO) for the provision of financial support in the framework of the PRODEX Programme of the European Space Agency (ESA) under contract number PEA 4000131343. DG, MF, SC, XB, and JL acknowledge their roles as ESA-appointed CHEOPS science team members. ZG was supported by the Hungarian NKFI grant No. K-119517 and the GINOP grant No. 2.3.2-15-2016-00003 of the Hungarian National Research Development and Innovation Office, by the City of Szombathely under agreement No. 67.177-21/2016, and by the VEGA grant of the Slovak Academy of Sciences No. 2/0031/18. This work was supported by FCT - Fundação para a Ciência e a Tecnologia through national funds and by FEDER through COMPETE2020 - Programa Operacional Competitividade e Internacionalização by these grants: UID/FIS/04434/2019; UIDB/04434/2020; UIDP/04434/2020; PTDC/FIS-AST/32113/2017 and POCI-01-0145-FEDER-032113; PTDC/FIS-AST/28953/2017 and POCI-01-0145-FEDER-028953; PTDC/FIS-AST/28987/2017 and POCI-01-0145-FEDER-028987. ACC and TGW acknowledge support from STFC consolidated grant No. ST/M001296/1. SH acknowledges CNES funding through the grant 837319. ODSD is supported in the form of work contract (DL 57/2016/CP1364/CT0004) funded by national funds through Fundação para a Ciência e Tecnologia (FCT). This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (project FOUR ACES; grant agreement No. 724427).

Published
2021
Full Text
View/download PDF

50. The EBLM project - VIII. First results for M-dwarf mass, radius, and effective temperature measurements using CHEOPS light curves

Author

David V. Martin, N. A. Walton, Isabelle Boisse, Giampaolo Piotto, Matthew P. Battley, Roberto Ragazzoni, A. Deline, Demetrio Magrin, J. Asquier, Roi Alonso, H. G. Floren, N. Miller, M. Steller, Pierre F. L. Maxted, Didier Queloz, Ignasi Ribas, Stéphane Udry, S. C. C. Barros, S. G. Sousa, C. Lovis, Kevin Heng, Manuel Guedel, G. Anglada Escudé, Sébastien Charnoz, Melissa J. Hobson, Monika Lendl, B.-O. Demory, M. I. Swayne, M. Beck, László L. Kiss, Nuno C. Santos, David Barrado, J. Cabrera, Willy Benz, Sz. Csizmadia, Thomas Beck, P. Guterman, Enric Palle, Damien Ségransan, Yann Alibert, Sergio Hoyer, G. Olofsson, Georgina Dransfield, Matthew R. Standing, Davide Gandolfi, S. Lalitha, N. Thomas, Alexis Brandeker, A. E. Simon, Wolfgang Baumjohann, Don Pollacco, C. Broeg, Guillaume Hébrard, Nascimbeni, Kunovac Hodžić, Alexis M. S. Smith, T. G. Wilson, Emma Willett, Nicola Rando, A. Bekkelien, M.-D. Busch, Ingo Walter, Van Grootel, A. Santerne, M. Fridlund, Gy. M. Szabó, David Ehrenreich, Nicolas Billot, James McCormac, K. G. Isaak, I. Pagano, Magali Deleuil, Andrea Fortier, S. Salmon, Xavier Bonfils, A. Lecavelier des Etangs, Heike Rauer, Laetitia Delrez, N. Heidari, Luca Fossati, Amaury H. M. J. Triaud, A. Collier Cameron, Melvyn B. Davies, G. Scandariato, Gisbert Peter, M. Steinberger, Luca Marafatto, D. Futyan, Roland Ottensamer, Jacques Laskar, Michaël Gillon, Anders Erikson, T. Bárczy, Olivier Demangeon, Coel Hellier, A. Bonfanti, Keele University [Keele], Instituto de Astrofísica e Ciências do Espaço (IASTRO), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science, and Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)

Subjects
Fundamental Parameters, Spectroscopic, 01 natural sciences, Categorical grant, spectroscopic [Techniques], techniques: photometric, stars: low-mass, QB460, QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, QC, media_common, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Horizon (archaeology), eclipsing [Binaries], 520 Astronomy, European research, 500 Naturwissenschaften und Mathematik::520 Astronomie::520 Astronomie und zugeordnete Wissenschaften, binaries: eclipsing, 3rd-DAS, Radius, 3. Good health, Astrophysics - Solar and Stellar Astrophysics, stars: fundamental parameters, Astrophysics::Earth and Planetary Astrophysics, Meteorology, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Photometric, fundamental parameters [Stars], low-mass [Stars], 0103 physical sciences, media_common.cataloged_instance, Low-Mass, European union, Eclipsing, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, QB600, 010308 nuclear & particles physics, photometric [Techniques], Binaries, Astronomy and Astrophysics, Effective temperature, 620 Engineering, Light curve, Stars, Techniques, QC Physics, Space and Planetary Science, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], techniques: spectroscopic, Astrophysics - Earth and Planetary Astrophysics
Abstract

The accuracy of theoretical mass, radius and effective temperature values for M-dwarf stars is an active topic of debate. Differences between observed and theoretical values have raised the possibility that current theoretical stellar structure and evolution models are inaccurate towards the low-mass end of the main sequence. To explore this issue we use the CHEOPS satellite to obtain high-precision light curves of eclipsing binaries with low mass stellar companions. We use these light curves combined with the spectroscopic orbit for the solar-type companion to measure the mass, radius and effective temperature of the M-dwarf star. Here we present the analysis of three eclipsing binaries. We use the pycheops data analysis software to fit the observed transit and eclipse events of each system. Two of our systems were also observed by the TESS satellite -- we similarly analyse these light curves for comparison. We find consistent results between CHEOPS and TESS, presenting three stellar radii and two stellar effective temperature values of low-mass stellar objects. These initial results from our on-going observing programme with CHEOPS show that we can expect to have ~24 new mass, radius and effective temperature measurements for very low mass stars within the next few years., Comment: 12 pages, 8 figures, accepted for publication in MNRAS

Published
2021
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results