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8 results on '"L. Zalesky"'

1. The Farmer: A Reproducible Profile-fitting Photometry Package for Deep Galaxy Surveys

Author

J. R. Weaver, L. Zalesky, V. Kokorev, C. J. R. McPartland, N. Chartab, K. M. L. Gould, M. Shuntov, I. Davidzon, A. Faisst, N. Stickley, P. L. Capak, S. Toft, D. Masters, B. Mobasher, D. B. Sanders, O. B. Kauffmann, H. J. McCracken, O. Ilbert, G. Brammer, and A. Moneti

Subjects
Photometry, Astrostatistics, Catalogs, Astrophysics, QB460-466
Abstract

While space-borne optical and near-infrared facilities have succeeded in delivering a precise and spatially resolved picture of our Universe, their small survey area is known to underrepresent the true diversity of galaxy populations. Ground-based surveys have reached comparable depths but at lower spatial resolution, resulting in source confusion that hampers accurate photometry extractions. What once was limited to the infrared regime has now begun to challenge ground-based ultradeep surveys, affecting detection and photometry alike. Failing to address these challenges will mean forfeiting a representative view into the distant Universe. We introduce The Farmer : an automated, reproducible profile-fitting photometry package that pairs a library of smooth parametric models from The Tractor with a decision tree that determines the best-fit model in concert with neighboring sources. Photometry is measured by fitting the models on other bands leaving brightness free to vary. The resulting photometric measurements are naturally total, and no aperture corrections are required. Supporting diagnostics (e.g., χ ^2 ) enable measurement validation. As fitting models is relatively time intensive, The Farmer is built with high-performance computing routines. We benchmark The Farmer on a set of realistic COSMOS-like images and find accurate photometry, number counts, and galaxy shapes. The Farmer is already being utilized to produce catalogs for several large-area deep extragalactic surveys where it has been shown to tackle some of the most challenging optical and near-infrared data available, with the promise of extending to other ultradeep surveys expected in the near future. The Farmer is available to download from GitHub ( https://github.com/astroweaver/the_farmer ) and Zenodo ( https://doi.org/10.5281/zenodo.8205817 ).

Published
2023
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2. COSMOS2020: a panchromatic view of the universe to z 10 from two complementary catalogs

Author

J. R. Weaver, O. B. Kauffmann, O. Ilbert, H. J. McCracken, A. Moneti, S. Toft, G. Brammer, M. Shuntov, I. Davidzon, B. C. Hsieh, C. Laigle, A. Anastasiou, C. K. Jespersen, J. Vinther, P. Capak, C. M. Casey, C. J. R. McPartland, B. Milvang-Jensen, B. Mobasher, D. B. Sanders, L. Zalesky, S. Arnouts, H. Aussel, J. S. Dunlop, A. Faisst, M. Franx, L. J. Furtak, J. P. U. Fynbo, K. M. L. Gould, T. R. Greve, S. Gwyn, J. S. Kartaltepe, D. Kashino, A. M. Koekemoer, V. Kokorev, O. Le Fèvre, S. Lilly, D. Masters, G. Magdis, V. Mehta, Y. Peng, D. A. Riechers, M. Salvato, M. Sawicki, C. Scarlata, N. Scoville, R. Shirley, J. D. Silverman, A. Sneppen, V. Smolc̆ić, C. Steinhardt, D. Stern, M. Tanaka, Y. Taniguchi, H. I. Teplitz, M. Vaccari, W.-H. Wang, G. Zamorani, 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 d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / 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-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Weaver, JR [0000-0003-1614-196X], Kauffmann, OB [0000-0001-5283-4662], Ilbert, O [0000-0002-7303-4397], McCracken, HJ [0000-0002-9489-7765], Toft, S [0000-0003-3631-7176], Brammer, G [0000-0003-2680-005X], Shuntov, M [0000-0002-7087-0701], Davidzon, I [0000-0002-2951-7519], Hsieh, BC [0000-0001-5615-4904], Anastasiou, A [0000-0001-8558-7709], Jespersen, CK [0000-0002-8896-6496], Vinther, J [0000-0002-4418-752X], Capak, P [0000-0003-3578-6843], Casey, CM [0000-0002-0930-6466], McPartland, CJR [0000-0003-0639-025X], Milvang-Jensen, B [0000-0002-2281-2785], Sanders, DB [0000-0002-1233-9998], Zalesky, L [0000-0001-5680-2326], Faisst, A [0000-0002-9382-9832], Franx, M [0000-0002-8871-3026], Furtak, LJ [0000-0001-6278-032X], Fynbo, JPU [0000-0002-8149-8298], Gould, KML [0000-0003-4196-5960], Greve, TR [0000-0002-2554-1837], Gwyn, S [0000-0001-8221-8406], Kartaltepe, JS [0000-0001-9187-3605], Kashino, D [0000-0001-9044-1747], Koekemoer, AM [0000-0002-6610-2048], Kokorev, V [0000-0002-5588-9156], Le Fèvre, O [0000-0001-5891-2596], Lilly, S [0000-0002-6423-3597], Masters, D [0000-0001-5382-6138], Magdis, G [0000-0002-4872-2294], Mehta, V [0000-0001-7166-6035], Riechers, DA [0000-0001-9585-1462], Salvato, M [0000-0001-7116-9303], Sawicki, M [0000-0002-7712-7857], Scarlata, C [0000-0002-9136-8876], Scoville, N [0000-0002-0438-3323], Shirley, R [0000-0002-1114-0135], Sneppen, A [0000-0002-5460-6126], Smolc̆ić, V [0000-0002-3893-8614], Steinhardt, C [0000-0003-3780-6801], Stern, D [0000-0003-2686-9241], Tanaka, M [0000-0002-5011-5178], Taniguchi, Y [0000-0003-2247-3741], Teplitz, HI [0000-0002-7064-5424], Vaccari, M [0000-0002-6748-0577], Wang, W-H [0000-0003-2588-1265], Zamorani, G [0000-0002-2318-301X], and Apollo - University of Cambridge Repository

Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO), Astrophysics - astrophysics of galaxies, Astrophysics - cosmology and nongalactic astrophysics, FOS: Physical sciences, 5109 Space Sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Galaxies and Cosmology, Universe, panchromatic view, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Galaxy Astrophysics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, 51 Physical Sciences
Abstract

The Cosmic Evolution Survey (COSMOS) has become a cornerstone of extragalactic astronomy. Since the last public catalog in 2015, a wealth of new imaging and spectroscopic data has been collected in the COSMOS field. This paper describes the collection, processing, and analysis of this new imaging data to produce a new reference photometric redshift catalog. Source detection and multi-wavelength photometry is performed for 1.7 million sources across the $2\,\mathrm{deg}^{2}$ of the COSMOS field, $\sim$966,000 of which are measured with all available broad-band data using both traditional aperture photometric methods and a new profile-fitting photometric extraction tool, The Farmer, which we have developed. A detailed comparison of the two resulting photometric catalogs is presented. Photometric redshifts are computed for all sources in each catalog utilizing two independent photometric redshift codes. Finally, a comparison is made between the performance of the photometric methodologies and of the redshift codes to demonstrate an exceptional degree of self-consistency in the resulting photometric redshifts. The $i, Comment: 39 pages, 21 figures, accepted for publication in The Astrophysical Journal Supplement Series. Production of IRAC mosaics are presented in Moneti et al. "Euclid Preparation: XVIII. Cosmic Dawn Survey. Spitzer observations of the Euclid deep fields and calibration fields" which has been posted simultaneously. Catalogs can be accessed online now at https://cosmos2020.calet.org

Published
2022
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4. Measuring the Innermost Stable Circular Orbits of Supermassive Black Holes

Author

Christopher S. Kochanek, Henric Krawczynski, George Chartas, Christopher W. Morgan, Ana M. Mosquera, Xinyu Dai, and L. Zalesky

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Supermassive black hole, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Quasar, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, 01 natural sciences, Accretion (astrophysics), Galaxy, Stars, Space and Planetary Science, 0103 physical sciences, Circular orbit, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Line (formation)
Abstract

We present a promising new technique, the g-distribution method, for measuring the inclination angle (i), the innermost stable circular orbit (ISCO), and the spin of a supermassive black hole. The g-distribution method uses measurements of the energy shifts in the relativistic iron line emitted by the accretion disk of a supermassive black hole due to microlensing by stars in a foreground galaxy relative to the g-distribution shifts predicted from microlensing caustic calculations. We apply the method to the gravitationally lensed quasars RX J1131-1231 (z_s=0.658, z_l=0.295), QJ 0158-4325 (z_s=1.294, z_l=0.317), and SDSS 1004+4112 (z_s=1.734, z_l=0.68). For RX J1131-1231 our initial results indicate that r_ISCO 76 degrees. We detect two shifted Fe lines, in several observations, as predicted in our numerical simulations of caustic crossings. The current DeltaE-distribution of RX J1131-1231 is sparsely sampled but further X-ray monitoring of RX J1131-1231 and other lensed quasars will provide improved constraints on the inclination angles, ISCO radii and spins of the black holes of distant quasars., 40 pages, includes 20 figures, Replaced with version accepted by The Astrophysical Journal

Published
2016

5. Integrating segmented electronic paper displays into consumer electronic devices

Author

Jonathan L. Zalesky and Amory Wakefield

Subjects
Engineering, Reliability (semiconductor), Power demand, business.industry, law, Low-power electronics, Electrical engineering, Electronic engineering, Power semiconductor device, Electronics, Electronic paper, business, law.invention
Abstract

Segmented electronic paper displays are ultra-low power devices, particularly in applications where information is not updated continuously. This paper will present a new integrated module design using standard interfaces and off-the-shelf processors. Also addressed are the reliability and lifetime performance of segmented electronic paper displays.

Published
2011
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8. Measuring the Innermost Stable Circular Orbits of Supermassive Black Holes.

Author

G. Chartas, H. Krawczynski, L. Zalesky, C. S. Kochanek, X. Dai, C. W. Morgan, and A. Mosquera

Subjects
SUPERMASSIVE black holes, ACCRETION (Astrophysics), MICROLENSING (Astrophysics), QUASARS, STELLAR orbits, GRAVITATIONAL lenses
Abstract

We present a promising new technique, the g-distribution method, for measuring the inclination angle (i), the innermost stable circular orbit (ISCO), and the spin of a supermassive black hole. The g-distribution method uses measurements of the energy shifts in the relativistic iron line emitted by the accretion disk of a supermassive black hole due to microlensing by stars in a foreground galaxy relative to the g-distribution shifts predicted from microlensing caustic calculations. We apply the method to the gravitationally lensed quasars RX J1131–1231 (zs = 0.658, zl = 0.295), QJ 0158–4325 (zs = 1.294, zl = 0.317), and SDSS 1004+4112 (zs = 1.734, zl = 0.68). For RX J1131−1231, our initial results indicate that rISCO ≲ 8.5 gravitational radii (rg) and i ≳ 55° (99% confidence level). We detect two shifted Fe lines in several observations, as predicted in our numerical simulations of caustic crossings. The current ΔE distribution of RX J1131–1231 is sparsely sampled, but further X-ray monitoring of RX J1131–1231 and other lensed quasars will provide improved constraints on the inclination angles, ISCO radii, and spins of the black holes of distant quasars. [ABSTRACT FROM AUTHOR]

Published
2017
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