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3. Exploring He II lambda 1640 emission line properties at z similar to 2-4

Author

Nanayakkara, W.T.T., Brinchmann, J., Boogaard, L.A., Bouwens, R.J., Cantalupo, S., Feltre, A., Kollatschny, W., Marino, R.A., Maseda, M.V., Matthee, J., Paalvast, M., Richard, J., and Verhamme, A.

Subjects
Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

Deep optical spectroscopic surveys of galaxies provide a unique opportunity to investigate rest-frame ultra-violet (UV) emission line properties of galaxies at z similar to 2-4.5. Here we combine VLT /MUSE Guaranteed Time Observations of the Hubble Deep Field South, Ultra Deep Field, COSMOS, and several quasar fields with other publicly available data from VLT /VIMOS and VLT /FORS2 to construct a catalogue of He II lambda 1640 emitters at z greater than or similar to 2. The deepest areas of our MUSE pointings reach a 3 sigma line flux limit of 3.1 x 10(19) erg s(-1) cm(-2). After discarding broad-line active galactic nuclei, we find 13 He II lambda 1640 detections from MUSE with a median M-UV = -20.1 and 21 tentative He II lambda 1640 detections from other public surveys. Excluding Ly alpha, all except two galaxies in our sample show at least one other rest-UV emission line, with C III] lambda 1907, lambda 1909 being the most prominent. We use multi-wavelength data available in the Hubble legacy fields to derive basic galaxy properties of our sample through spectral energy distribution fitting techniques. Taking advantage of the high-quality spectra obtained by MUSE (similar to 10-30 h of exposure time per pointing), we use photo-ionisation models to study the rest-UV emission line diagnostics of the He II lambda 1640 emitters. Line ratios of our sample can be reproduced by moderately sub-solar photo-ionisation models, however, we find that including effects of binary stars lead to degeneracies in most free parameters. Even after considering extra ionising photons produced by extreme sub-solar metallicity binary stellar models, photo-ionisation models are unable to reproduce rest-frame He II lambda 1640 equivalent widths (similar to 0.2-10 angstrom), thus additional mechanisms are necessary in models to match the observed He II lambda 1640 properties.

Published
2019

6. MEGARA, the R=6000-20000 IFU and MOS of GTC

Author

Carrasco, E., Gil de Paz, A., Gallego, J., Iglesias-Páramo, J., Cedazo, R., García Vargas, M. L., Arrillaga, X., Avilés, J. L., Bouquin, A., Carbajo, J., Cardiel, Nicolás, Carrera, M. A., Castillo Morales, A., Castillo-Domínguez, E., Esteban San Román, S., Ferrusca, D., Gómez-Álvarez, P., Izazaga-Pérez, R., Lefort, B., López Orozco, J. A., Maldonado, M., Martínez Delgado, Ismael, Morales Durán, I., Mújica, E., Ortiz, R., Páez, G., Pascual, S., Pérez-Calpena, A., Picazo, P., Sánchez-Penim, A., Sánchez-Blanco, E., Tulloch, S., Velázquez, M., Vílchez Medina, José Manuel, Zamorano, J., Aguerri, A. L., Barrado y Navascués, David, Bertone, E., Cava, A., Catalán-Torrecilla, C., Cenarro, J., Chávez, M., Dullo, B. T., Eliche, C., García, Miriam, García-Rojas, J., Guichard, J., González-Delgado, R., Guzmán, R., Herrero, A., Huélamo, Nuria, Hughes, D. H., Jiménez-Vicente, J., Kehrig, C., Marino, R.A., Márquez, Isabel, Masegosa, Josefa, Mayya, D., Méndez-Abreu, J., Mollá, M., Muñoz-Tuñón, C., Peimbert, M., Pérez-González, Pablo G., Pérez Montero, Enrique, Roca-Fàbrega, S., Rodríguez, M., Rodríguez-Espinosa, J. M., Rodríguez-Merino, L., Rodríguez-Muñoz, L., González Delgado, Rosa M., Sánchez-Almeida, J., Sánchez Contreras, C., Sánchez-Blázquez, P., Sánchez, Sebastián F., Sarajedini, A., Silich, S., Simón-Díaz, S., Tenorio-Tagle, G., Terlevich, E., Terlevich, R., Torres-Peimbert, S., Trujillo, I., Tsamis, Y., Vega, O., Carrasco, E., Gil de Paz, A., Gallego, J., Iglesias-Páramo, J., Cedazo, R., García Vargas, M. L., Arrillaga, X., Avilés, J. L., Bouquin, A., Carbajo, J., Cardiel, Nicolás, Carrera, M. A., Castillo Morales, A., Castillo-Domínguez, E., Esteban San Román, S., Ferrusca, D., Gómez-Álvarez, P., Izazaga-Pérez, R., Lefort, B., López Orozco, J. A., Maldonado, M., Martínez Delgado, Ismael, Morales Durán, I., Mújica, E., Ortiz, R., Páez, G., Pascual, S., Pérez-Calpena, A., Picazo, P., Sánchez-Penim, A., Sánchez-Blanco, E., Tulloch, S., Velázquez, M., Vílchez Medina, José Manuel, Zamorano, J., Aguerri, A. L., Barrado y Navascués, David, Bertone, E., Cava, A., Catalán-Torrecilla, C., Cenarro, J., Chávez, M., Dullo, B. T., Eliche, C., García, Miriam, García-Rojas, J., Guichard, J., González-Delgado, R., Guzmán, R., Herrero, A., Huélamo, Nuria, Hughes, D. H., Jiménez-Vicente, J., Kehrig, C., Marino, R.A., Márquez, Isabel, Masegosa, Josefa, Mayya, D., Méndez-Abreu, J., Mollá, M., Muñoz-Tuñón, C., Peimbert, M., Pérez-González, Pablo G., Pérez Montero, Enrique, Roca-Fàbrega, S., Rodríguez, M., Rodríguez-Espinosa, J. M., Rodríguez-Merino, L., Rodríguez-Muñoz, L., González Delgado, Rosa M., Sánchez-Almeida, J., Sánchez Contreras, C., Sánchez-Blázquez, P., Sánchez, Sebastián F., Sarajedini, A., Silich, S., Simón-Díaz, S., Tenorio-Tagle, G., Terlevich, E., Terlevich, R., Torres-Peimbert, S., Trujillo, I., Tsamis, Y., and Vega, O.

Abstract

MEGARA is the new generation IFU and MOS optical spectrograph built for the 10.4m Gran Telescopio CANARIAS (GTC). The project was developed by a consortium led by UCM (Spain) that also includes INAOE (Mexico), IAA-CSIC (Spain) and UPM (Spain). The instrument arrived to GTC on March 28th 2017 and was successfully integrated and commissioned at the telescope from May to August 2017. During the on-sky commissioning we demonstrated that MEGARA is a powerful and robust instrument that provides on-sky intermediate-to-high spectral resolutions RFWHM ~ 6,000, 12,000 and 20,000 at an unprecedented efficiency for these resolving powers in both its IFU and MOS modes. The IFU covers 12.5 x 11.3 arcsec 2 while the MOS mode allows observing up to 92 objects in a region of 3.5 x 3.5 arcmin 2 . In this paper we describe the instrument main subsystems, including the Folded-Cassegrain unit, the fiber link, the spectrograph, the cryostat, the detector and the control subsystems, and its performance numbers obtained during commissioning where the fulfillment of the instrument requirements is demonstrated. © 2018 SPIE.

Published
2018

7. First scientific observations with MEGARA at GTC

Author

Gil de Paz, A., Carrasco, E., Gallego, J., Iglesias-Páramo, J., Cedazo, R., García-Vargas, M. L., Arrillaga, X., Avilés, J. L., Bouquin, A., Carbajo, J., Cardiel, Nicolás, Carrera, M. A., Castillo-Morales, A., Castillo-Domínguez, E., Esteban San Román, S., Ferrusca, D., Gómez-Álvarez, P., Izazaga-Pérez, R., Lefort, B., López-Orozco, J. A., Maldonado, M., Martínez-Delgado, I., Morales-Durán, I., Mújica, E., Páez, G., Pascual, S., Pérez-Calpena, A., Picazo, P., Sánchez-Penim, A., Sánchez-Blanco, E., Tulloch, S., Velázquez, M., Vílchez Medina, José Manuel, Zamorano, J., Aguerri, A. L., Barrado y Navascués, David, Berlanas, S. R., Bertone, E., Cava, A., Catalán-Torrecilla, C., Cenarro, J., Chávez, M., Dullo, B. T., García, M., García-Rojas, J., Guichard, J., González Delgado, Rosa M., Guzmán, R., Herrero, A., Huélamo, Nuria, Hughes, D. H., Jiménez-Vicente, J., Kehrig, C., Marino, R.A., Márquez, Isabel, Masegosa, Josefa, Mayya, D., Méndez-Abreu, J., Mollá, M., Muñoz-Tuñón, C., Peimbert, M., Pérez-González, Pablo G., Pérez Montero, Enrique, Rodríguez, M., Rodríguez-Espinosa, J. M., Rodríguez Merino, L., Rodríguez-Muñoz, L., Rosa González, Daniel, Sánchez-Almeida, J., Sánchez Contreras, C., Sánchez-Blázquez, P., Sánchez, Sebastián F., Sarajedini, A., Silich, S., Simón-Díaz, S., Tenorio-Tagle, G., Terlevich, E., Terlevich, R., Torres-Peimbert, S., Trujillo, I., Tsamis, Y., Vega, O., Gil de Paz, A., Carrasco, E., Gallego, J., Iglesias-Páramo, J., Cedazo, R., García-Vargas, M. L., Arrillaga, X., Avilés, J. L., Bouquin, A., Carbajo, J., Cardiel, Nicolás, Carrera, M. A., Castillo-Morales, A., Castillo-Domínguez, E., Esteban San Román, S., Ferrusca, D., Gómez-Álvarez, P., Izazaga-Pérez, R., Lefort, B., López-Orozco, J. A., Maldonado, M., Martínez-Delgado, I., Morales-Durán, I., Mújica, E., Páez, G., Pascual, S., Pérez-Calpena, A., Picazo, P., Sánchez-Penim, A., Sánchez-Blanco, E., Tulloch, S., Velázquez, M., Vílchez Medina, José Manuel, Zamorano, J., Aguerri, A. L., Barrado y Navascués, David, Berlanas, S. R., Bertone, E., Cava, A., Catalán-Torrecilla, C., Cenarro, J., Chávez, M., Dullo, B. T., García, M., García-Rojas, J., Guichard, J., González Delgado, Rosa M., Guzmán, R., Herrero, A., Huélamo, Nuria, Hughes, D. H., Jiménez-Vicente, J., Kehrig, C., Marino, R.A., Márquez, Isabel, Masegosa, Josefa, Mayya, D., Méndez-Abreu, J., Mollá, M., Muñoz-Tuñón, C., Peimbert, M., Pérez-González, Pablo G., Pérez Montero, Enrique, Rodríguez, M., Rodríguez-Espinosa, J. M., Rodríguez Merino, L., Rodríguez-Muñoz, L., Rosa González, Daniel, Sánchez-Almeida, J., Sánchez Contreras, C., Sánchez-Blázquez, P., Sánchez, Sebastián F., Sarajedini, A., Silich, S., Simón-Díaz, S., Tenorio-Tagle, G., Terlevich, E., Terlevich, R., Torres-Peimbert, S., Trujillo, I., Tsamis, Y., and Vega, O.

Abstract

On June 25th 2017, the new intermediate-resolution optical IFU and MOS of the 10.4-m GTC had its first light. As part of the tests carried out to verify the performance of the instrument in its two modes (IFU and MOS) and 18 spectral setups (identical number of VPHs with resolutions R=6000-20000 from 0.36 to 1 micron) a number of astronomical objects were observed. These observations show that MEGARA@GTC is called to fill a niche of high-throughput, intermediateresolution IFU and MOS observations of extremely-faint narrow-lined objects. Lyman-¿ absorbers, star-forming dwarfs or even weak absorptions in stellar spectra in our Galaxy or in the Local Group can now be explored to a new level. Thus, the versatility of MEGARA in terms of observing modes and spectral resolution and coverage will allow GTC to go beyond current observational limits in either depth or precision for all these objects. The results to be presented in this talk clearly demonstrate the potential of MEGARA in this regard. © 2018 SPIE.

Published
2018

8. The MUSE-Wide survey: detection of a clustering signal from Lyman α emitters in the range 3 < z < 6

Author

Diener , C., Wisotzki , L., Schmidt , K.B., Herenz , E.C., Urrutia , T., Garel , T., Kerutt , J., Saust , R.L., Bacon , R., Cantalupo , S., Contini , T., Guiderdoni , B., Marino , R.A., Richard , J., Schaye , J., Soucail , G., Weilbacher , P.M., Centre de Recherche Astrophysique de Lyon ( CRAL ), École normale supérieure - Lyon ( ENS Lyon ) -Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), École normale supérieure - Lyon ( ENS Lyon ), Institut de recherche en astrophysique et planétologie ( IRAP ), and Université Paul Sabatier - Toulouse 3 ( UPS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS )

Subjects
galaxies: high-redshift, cosmology: observations, [ PHYS.ASTR ] Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; We present a clustering analysis of a sample of 238 Ly α emitters at redshift 3 ≲ z ≲ 6 from the MUSE-Wide survey. This survey mosaics extragalactic legacy fields with 1h MUSE pointings to detect statistically relevant samples of emission line galaxies. We analysed the first year observations from MUSE-Wide making use of the clustering signal in the line-of-sight direction. This method relies on comparing pair-counts at close redshifts for a fixed transverse distance and thus exploits the full potential of the redshift range covered by our sample. A clear clustering signal with a correlation length of $$r_{0}=2.9^{+1.0}_{-1.1}$$ Mpc (comoving) is detected. Whilst this result is based on only about a quarter of the full survey size, it already shows the immense potential of MUSE for efficiently observing and studying the clustering of Ly α emitters.

Published
2017
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9. MUSE deep-fields: the Ly alpha luminosity function in the Hubble Deep Field-South at 2.91 < z < 6.64

Author

Drake, A.B., Guiderdoni, B., Blaizot, J., Wisotzki, L., Herenz, E.C., Garel, T., Richard, J., Bacon, R., Bina, D., Cantalupo, S., Contini, T., Brok, M., Hashimoto, T., Marino, R.A., Pelló, R., Schaye, J., and Schmidt, K.B.

Subjects
galaxies: luminosity functions, surveys, galaxies: high-redshift, luminosity functions, mass function, cosmology: observations, galaxies: evolution, galaxies: formation, galaxies: high-redshift [galaxies]
Abstract

We present the first estimate of the Ly α luminosity function using blind spectroscopy from the Multi Unit Spectroscopic Explorer, MUSE, in the Hubble Deep Field-South. Using automatic source-detection software, we assemble a homogeneously detected sample of 59 Ly α emitters covering a flux range of −18.0 < log10 (F) < −16.3 (erg s−1 cm−2), corresponding to luminosities of 41.4 < log10 (L) < 42.8 (erg s−1). As recent studies have shown, Ly α fluxes can be underestimated by a factor of 2 or more via traditional methods, and so we undertake a careful assessment of each object's Ly α flux using a curve-of-growth analysis to account for extended emission. We describe our self-consistent method for determining the completeness of the sample, and present an estimate of the global Ly α luminosity function between redshifts 2.91 < z < 6.64 using the 1/Vmax estimator. We find that the luminosity function is higher than many number densities reported in the literature by a factor of 2–3, although our result is consistent at the 1σ level with most of these studies. Our observed luminosity function is also in good agreement with predictions from semi-analytic models, and shows no evidence for strong evolution between the high- and low-redshift halves of the data. We demonstrate that one's approach to Ly α flux estimation does alter the observed luminosity function, and caution that accurate flux assessments will be crucial in measurements of the faint-end slope. This is a pilot study for the Ly α luminosity function in the MUSE deep-fields, to be built on with data from the Hubble Ultra Deep Field that will increase the size of our sample by almost a factor of 10., Monthly Notices of the Royal Astronomical Society, 471 (1), ISSN:0035-8711, ISSN:1365-2966, ISSN:1365-8711

Published
2017

10. Arm and interarm abundance gradients in CALIFA spiral galaxies

Author

Sánchez-Menguiano, L, Sánchez, S.F, Pérez, I., Debattista, Victor P, Ruiz-Lara, T, Florido, E, Cavichia, O, Galbany, L, Marino, R.A, Mast, D, Sánchez-Blázquez, P, Méndez-Abreu, J, De Lorenzo-Cáceres, A, Catalán-Torrecilla, C, Cano-Díaz, M, Márquez, I, McIntosh, D.H, Ascasibar, Y, García-Benito, R, González Delgado, R.M, Kehrig, C, López-Sánchez, A.R, Molla, M, Bland-Hawthorn, J, Walcher, C.J, Costantin, L, Sánchez-Menguiano, L, Sánchez, S.F, Pérez, I., Debattista, Victor P, Ruiz-Lara, T, Florido, E, Cavichia, O, Galbany, L, Marino, R.A, Mast, D, Sánchez-Blázquez, P, Méndez-Abreu, J, De Lorenzo-Cáceres, A, Catalán-Torrecilla, C, Cano-Díaz, M, Márquez, I, McIntosh, D.H, Ascasibar, Y, García-Benito, R, González Delgado, R.M, Kehrig, C, López-Sánchez, A.R, Molla, M, Bland-Hawthorn, J, Walcher, C.J, and Costantin, L

Abstract

Spiral arms are the most singular features in disc galaxies. These structures can exhibit different patterns, namely grand design and flocculent arms, with easily distinguishable characteristics. However, their origin and the mechanisms shaping them are unclear. The overall role of spirals in the chemical evolution of disc galaxies is another unsolved question. In particular, it has not been fully explored if the H ii regions of spiral arms present different properties from those located in the interarm regions. Here we analyse the radial oxygen abundance gradient of the arm and interarm star forming regions of 63 face-on spiral galaxies using CALIFA Integral Field Spectroscopy data. We focus the analysis on three characteristic parameters of the profile: slope, zero-point, and scatter. The sample is morphologically separated into flocculent versus grand design spirals and barred versus unbarred galaxies. We find subtle but statistically significant differences betweenthe arm and interarm distributions for flocculent galaxies, suggesting that the mechanisms generating the spiral structure in these galaxies may be different to those producing grand design systems, for which no significant differences are found. We also find small differences in barred galaxies, not observed in unbarred systems, hinting that bars may affect the chemical distribution of these galaxies but not strongly enough as to be reflected in the overall abundance distribution. In light of these results, we propose bars and flocculent structure as two distinct mechanisms inducing differences in the abundance distribution between arm and interarm star forming regions.

Published
2017

11. Arm and interarm abundance gradients in CALIFA spiral galaxies

Author

Ministerio de Economía, Industria y Competitividad (España), Junta de Andalucía, Consejo Nacional de Ciencia y Tecnología (México), National Science Foundation (US), Swiss National Science Foundation, European Research Council, Sánchez-Menguiano, L., Sánchez, S.F., Pérez, I., Debattista, V.P., Ruiz-Lara, T., Florido, E., Cavichia, O., Galbany, Lluís, Marino, R.A., Mast, D., Sánchez-Blázquez, P., Méndez-Abreu, J., de Lorenzo-Cáceres, A., Catalán-Torrecilla, C., Cano-Díaz, M., Márquez, Isabel, McIntosh, D.H., Ascasíbar, Y., García-Benito, Rubén, González Delgado, Rosa M., Kehrig, C., López-Sánchez, R., Mollá, M., Bland-Hawthorn, J., Walcher, C.J., Costantin, L., Ministerio de Economía, Industria y Competitividad (España), Junta de Andalucía, Consejo Nacional de Ciencia y Tecnología (México), National Science Foundation (US), Swiss National Science Foundation, European Research Council, Sánchez-Menguiano, L., Sánchez, S.F., Pérez, I., Debattista, V.P., Ruiz-Lara, T., Florido, E., Cavichia, O., Galbany, Lluís, Marino, R.A., Mast, D., Sánchez-Blázquez, P., Méndez-Abreu, J., de Lorenzo-Cáceres, A., Catalán-Torrecilla, C., Cano-Díaz, M., Márquez, Isabel, McIntosh, D.H., Ascasíbar, Y., García-Benito, Rubén, González Delgado, Rosa M., Kehrig, C., López-Sánchez, R., Mollá, M., Bland-Hawthorn, J., Walcher, C.J., and Costantin, L.

Abstract

Spiral arms are the most singular features in disc galaxies. These structures can exhibit different patterns, namely grand design and flocculent arms, with easily distinguishable characteristics. However, their origin and the mechanisms shaping them are unclear. The overall role of spirals in the chemical evolution of disc galaxies is another unsolved question. In particular, it has not been fully explored if the H ii regions of spiral arms present different properties from those located in the interarm regions. Here we analyse the radial oxygen abundance gradient of the arm and interarm star forming regions of 63 face-on spiral galaxies using CALIFA Integral Field Spectroscopy data. We focus the analysis on three characteristic parameters of the profile: slope, zero-point, and scatter. The sample is morphologically separated into flocculent versus grand design spirals and barred versus unbarred galaxies. We find subtle but statistically significant differences betweenthe arm and interarm distributions for flocculent galaxies, suggesting that the mechanisms generating the spiral structure in these galaxies may be different to those producing grand design systems, for which no significant differences are found. We also find small differences in barred galaxies, not observed in unbarred systems, hinting that bars may affect the chemical distribution of these galaxies but not strongly enough as to be reflected in the overall abundance distribution. In light of these results, we propose bars and flocculent structure as two distinct mechanisms inducing differences in the abundance distribution between arm and interarm star forming regions.© ESO, 2017.

Published
2017

12. Observational hints of radial migration in disc galaxies from CALIFA

Author

Consejo Nacional de Ciencia y Tecnología (México), Swiss National Science Foundation, European Research Council, Ministerio de Economía y Competitividad (España), National Science Foundation (US), Junta de Andalucía, Ministerio de Ciencia e Innovación (España), European Commission, Ruiz-Lara, T., Pérez, I., Florido, E., Sánchez-Blázquez, P., Méndez-Abreu, J., Sánchez Menguiano, Laura, Sánchez, S.F., Lyubenova, M., Falcón-Barroso, Jesús, Van De Ven, G., Marino, R.A., de Lorenzo-Cáceres, A., Catalán-Torrecilla, C., Costantin, L., Bland-Hawthorn, J., Galbany, Lluís, García-Benito, Rubén, Husemann, B., Kehrig, C., Márquez, Isabel, Mast, D., Walcher, C.J., Zibetti, S., Ziegler, B., Consejo Nacional de Ciencia y Tecnología (México), Swiss National Science Foundation, European Research Council, Ministerio de Economía y Competitividad (España), National Science Foundation (US), Junta de Andalucía, Ministerio de Ciencia e Innovación (España), European Commission, Ruiz-Lara, T., Pérez, I., Florido, E., Sánchez-Blázquez, P., Méndez-Abreu, J., Sánchez Menguiano, Laura, Sánchez, S.F., Lyubenova, M., Falcón-Barroso, Jesús, Van De Ven, G., Marino, R.A., de Lorenzo-Cáceres, A., Catalán-Torrecilla, C., Costantin, L., Bland-Hawthorn, J., Galbany, Lluís, García-Benito, Rubén, Husemann, B., Kehrig, C., Márquez, Isabel, Mast, D., Walcher, C.J., Zibetti, S., and Ziegler, B.

Abstract

Context. According to numerical simulations, stars are not always kept at their birth galactocentric distances but they have a tendency to migrate. The importance of this radial migration in shaping galactic light distributions is still unclear. However, if radial migration is indeed important, galaxies with different surface brightness (SB) profiles must display differences in their stellar population properties. Aims. We investigate the role of radial migration in the light distribution and radial stellar content by comparing the inner colour, age, and metallicity gradients for galaxies with different SB profiles. We define these inner parts, avoiding the bulge and bar regions and up to around three disc scale lengths (type I, pure exponential) or the break radius (type II, downbending; type III, upbending). Methods. We analysed 214 spiral galaxies from the CALIFA survey covering different SB profiles. We made use of GASP2D and SDSS data to characterise the light distribution and obtain colour profiles of these spiral galaxies. The stellar age and metallicity profiles were computed using a methodology based on full-spectrum fitting techniques (pPXF, GANDALF, and STECKMAP) to the Integral Field Spectroscopic CALIFA data. Results. The distributions of the colour, stellar age, and stellar metallicity gradients in the inner parts for galaxies displaying different SB profiles are unalike as suggested by Kolmogorov-Smirnov and Anderson-Darling tests. We find a trend in which type II galaxies show the steepest profiles of all, type III show the shallowest, and type I display an intermediate behaviour. Conclusions. These results are consistent with a scenario in which radial migration is more efficient for type III galaxies than for type I systems, where type II galaxies present the lowest radial migration efficiency. In such a scenario, radial migration mixes the stellar content, thereby flattening the radial stellar properties and shaping different SB profiles. However

Published
2017

13. The dependence of oxygen and nitrogen abundances on stellar mass from the CALIFA survey

Author

Fondo Nacional de Desarrollo Científico y Tecnológico (Chile), Junta de Andalucía, Ministerio de Ciencia e Innovación (España), Pérez Montero, Enrique, García-Benito, Rubén, Vílchez Medina, José Manuel, Sánchez, Sebastián F., Kehrig, C., Husemann, B., Duarte Puertas, Salvador, Iglesias-Páramo, J., Galbany, Lluís, Mollá, M., Walcher, C.J., Ascasíbar, Y., González Delgado, Rosa M., Marino, R.A., Masegosa, Josefa, Pérez Jiménez, Enrique, Rosales-Ortega, Fabián, Sánchez-Blázquez, P., Bland-Hawthorn, J., Bomans, D. J., López-Sánchez, A.R., Ziegler, B., Fondo Nacional de Desarrollo Científico y Tecnológico (Chile), Junta de Andalucía, Ministerio de Ciencia e Innovación (España), Pérez Montero, Enrique, García-Benito, Rubén, Vílchez Medina, José Manuel, Sánchez, Sebastián F., Kehrig, C., Husemann, B., Duarte Puertas, Salvador, Iglesias-Páramo, J., Galbany, Lluís, Mollá, M., Walcher, C.J., Ascasíbar, Y., González Delgado, Rosa M., Marino, R.A., Masegosa, Josefa, Pérez Jiménez, Enrique, Rosales-Ortega, Fabián, Sánchez-Blázquez, P., Bland-Hawthorn, J., Bomans, D. J., López-Sánchez, A.R., and Ziegler, B.

Abstract

Context. The study of the integrated properties of star-forming galaxies is central to understand their formation and evolution. Some of these properties are extensive and therefore their analysis require totally covering and spatially resolved observations. Among these properties, metallicity can be defined in spiral discs by means of integral field spectroscopy (IFS) of individual H ii regions. The simultaneous analysis of the abundances of primary elements, as oxygen, and secondary, as nitrogen, also provides clues about the star formation history and the processes that shape the build-up of spiral discs. Aims. Our main aim is to analyse simultaneously O/H and N/O abundance ratios in H ii regions in different radial positions of the discs in a large sample of spiral galaxies to obtain the slopes and the characteristic abundance ratios that can be related to their integrated properties. Methods. We analysed the optical spectra of individual selected H ii regions extracted from a sample of 350 spiral galaxies of the CALIFA survey. We calculated total O/H abundances and, for the first time, N/O ratios using the semi-empirical routine Hii-Chi-mistry, which, according to Pérez-Montero (2014, MNRAS, 441, 2663), is consistent with the direct method and reduces the uncertainty in the O/H derivation using [N ii] lines owing to the dispersion in the O/H-N/O relation. Then we performed linear fittings to the abundances as a function of the de-projected galactocentric distances. Results. The analysis of the radial distribution both for O/H and N/O in the non-interacting galaxies reveals that both average slopes are negative, but a non-negligible fraction of objects have a flat or even a positive gradient (at least 10% for O/H and 4% for N/O). The slopes normalised to the effective radius appear to have a slight dependence on the total stellar mass and the morphological type, as late low-mass objects tend to have flatter slopes. No clear relation is found, however, to explain

Published
2016

14. Outer-disk reddening and gas-phase metallicities: The CALIFA connection

Author

Campus de Excelencia Internacional Moncloa, Ministerio de Economía y Competitividad (España), European Commission, Ministerio de Educación, Cultura y Deporte (España), Instituto Milenio de Astrofísica (Chile), Comisión Nacional de Investigación Científica y Tecnológica (Chile), Fondo Nacional de Desarrollo Científico y Tecnológico (Chile), Consejo Nacional de Ciencia y Tecnología (México), European Research Council, Fundação para a Ciência e a Tecnologia (Portugal), Marino, R.A., Sánchez, Sebastián F., Cardiel, Nicolás, Vílchez Medina, José Manuel, Kehrig, C., González Delgado, Rosa M., García-Benito, Rubén, Mast, Damián, Iglesias-Páramo, J., Bland-Hawthorn, J., Campus de Excelencia Internacional Moncloa, Ministerio de Economía y Competitividad (España), European Commission, Ministerio de Educación, Cultura y Deporte (España), Instituto Milenio de Astrofísica (Chile), Comisión Nacional de Investigación Científica y Tecnológica (Chile), Fondo Nacional de Desarrollo Científico y Tecnológico (Chile), Consejo Nacional de Ciencia y Tecnología (México), European Research Council, Fundação para a Ciência e a Tecnologia (Portugal), Marino, R.A., Sánchez, Sebastián F., Cardiel, Nicolás, Vílchez Medina, José Manuel, Kehrig, C., González Delgado, Rosa M., García-Benito, Rubén, Mast, Damián, Iglesias-Páramo, J., and Bland-Hawthorn, J.

Abstract

We study, for the first time in a statistically significant and well-defined sample, the relation between the outer-disk ionized-gas metallicity gradients and the presence of breaks in the surface brightness profiles of disk galaxies. Sloan Digital Sky Survey (SDSS) g′- and r′-band surface brightness, (g′ - r′) color, and ionized-gas oxygen abundance profiles for 324 galaxies within the Calar Alto Legacy Integral Field Area (CALIFA) survey are used for this purpose. We perform a detailed light-profile classification, finding that 84% of our disks show down- or up-bending profiles (Type II and Type III, respectively), while the remaining 16% are well fitted by one single exponential (Type I). The analysis of the color gradients at both sides of this break shows a U-shaped profile for most Type II galaxies with an average minimum (g′ - r′) color of ∼ 0.5mag and an ionized-gas metallicity flattening associated with it only in the case of low-mass galaxies. Comparatively, more massive systems show a rather uniform negative metallicity gradient. The correlation between metallicity flattening and stellar mass for these systems results in p-values as low as 0.01. Independent of the mechanism having shaped the outer light profiles of these galaxies, stellar migration or a previous episode of star formation in a shrinking star-forming disk, it is clear that the imprint in their ionized-gas metallicity was different for low- and high-mass Type II galaxies. In the case of Type III disks, a positive correlation between the change in color and abundance gradient is found (the null hypothesis is ruled out with a p-value of 0.02), with the outer disks of Type III galaxies with masses ≤10 M′ showing a weak color reddening or even a bluing. This is interpreted as primarily due to a mass downsizing effect on the population of Type III galaxies that recently experienced an enhanced inside-out growth.

Published
2016

16. The MUSE Hubble Ultra Deep Field Survey X. Ly$\alpha$ Equivalent Widths at $2.9 < z < 6.6$

Author

Hashimoto, T., Garel, T., Guiderdoni, B., Drake, A.B., Bacon, R., Blaizot, J., Richard, J., Leclercq, F., Inami, H., Verhamme, A., Bouwens, R.J., Brinchmann, J., Cantalupo, S., Carollo, M., Caruana, J., Herenz, E.C., Kerutt, J., Marino, R.A., Mitchell, P., Schaye, J., Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], galaxies: high-redshift, Galaxy: formation, [SDU]Sciences of the Universe [physics], early Universe, high-redshift, galaxies: evolution, early Universe [galaxies], Astrophysics - Astrophysics of Galaxies, observations, galaxies: formation, galaxies: high-redshift [cosmology]
Abstract

We present rest-frame Ly$\alpha$ equivalent widths (EW) of 417 Ly$\alpha$ emitters (LAEs) detected with Multi Unit Spectroscopic Explorer (MUSE) on the Very Large Telescope (VLT) at $2.9 < z < 6.6$ in the Hubble Ultra Deep Field. Based on the deep MUSE spectroscopy and ancillary Hubble Space Telescope (HST) photometry data, we carefully measured EW values taking into account extended Ly$\alpha$ emission and UV continuum slopes ($\beta$). Our LAEs reach unprecedented depths, both in Ly$\alpha$ luminosities and UV absolute magnitudes, from log($L_{\rm Ly\alpha}$/erg s$^{-1}$) $\sim$41.0 to 43.0 and from Muv $\sim$ -16 to -21 (0.01-1.0 $L^{*}_{\rm z=3}$). The EW values span the range of $\sim$ 5 to 240 \AA\ or larger, and their distribution can be well fitted by an exponential law $N = N_{\rm 0}$ exp($-$EW/$w_{\rm 0}$). Owing to the high dynamic range in Muv, we find that the scale factor, $w_{\rm 0}$, depends on Muv in the sense that including fainter Muv objects increases $w_{\rm 0}$, i.e., the Ando effect. The results indicate that selection functions affect the EW scale factor. Taking these effects into account, we find that our $w_{\rm 0}$ values are consistent with those in the literature within $1\sigma$ uncertainties at $2.9 < z < 6.6$ at a given threshold of Muv and $L_{\rm Ly\alpha}$. Interestingly, we find 12 objects with EW $>200$ \AA\ above $1\sigma$ uncertainties. Two of these 12 LAEs show signatures of merger or AGN activity: the weak CIV $\lambda 1549$ emission line. For the remaining 10 very large EW LAEs, we find that the EW values can be reproduced by young stellar ages ($< 100$ Myr) and low metallicities ($\lesssim 0.02$ $Z_{\rm \odot}$). Otherwise, at least part of the Ly$\alpha$ emission in these LAEs needs to arise from anisotropic radiative transfer effects, fluorescence by hidden AGN or quasi-stellar object activity, or gravitational cooling., Comment: 22 pages, 12 figures, 9 tables, accepted for publication in A&A (MUSE UDF Series Paper X)

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26. 14N nuclear quadrupole resonance in the ferroelectric phase of sodium nitrite

Author

Oja, T., Marino, R.A., and Bray, P.J.

Abstract

Nitrogen-14 nuclear quadrupole resonance lines have been observed in the ferroelectric phase of sodium nitrite (NaNO2) and the change of nuclear quadrupole resonance frequencies with temperature between 77°K and the phase transition temperature (437°K) has been investigated. Attempts to fit the Bayer theory to the experimental results have not been successful.

Published
1967
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