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Your search keyword '"Joshi, Bhavin A"' showing total 3 results
Start Over Author "Joshi, Bhavin A" Topic star formation
3 results on '"Joshi, Bhavin A"'

1. The Reliability of Type Ia Supernovae Delay-time Distributions Recovered from Galaxy Star Formation Histories.

Author

Joshi, Bhavin A., Strolger, Louis-Gregory, and Zenati, Yossef

Subjects
*TYPE I supernovae, *MARKOV chain Monte Carlo, *STELLAR populations, *STAR formation, *GALAXY formation
Abstract

We present a numerical analysis investigating the reliability of Type Ia supernova (SN Ia) delay-time distributions recovered from individual host galaxy star formation histories. We utilize star formation histories of mock samples of galaxies generated from the IllustrisTNG simulation at two redshifts to recover delay-time distributions. The delay-time distributions are constructed through piecewise constants as opposed to typically employed parametric forms such as power laws or Gaussian or skew/lognormal functions. The SN Ia delay-time distributions are recovered through a Markov Chain Monte Carlo exploration of the likelihood space by comparing the expected SN Ia rate within each mock galaxy to the observed rate. We show that a reduced representative sample of nonhost galaxies is sufficient to reliably recover delay-time distributions while simultaneously reducing the computational load. We also highlight a potential systematic between recovered delay-time distributions and the mass-weighted ages of the underlying host galaxy stellar population. [ABSTRACT FROM AUTHOR]

Published
2024
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2. A Two-Dimensional Spectroscopic Study of Emission Line Galaxies in the Faint Infrared Grism Survey (FIGS) I: Detection Method and Catalog

Author

Pirzkal, Norbert, Rothberg, Barry, Ryan, Russell E., Malhotra, Sangeeta, Rhoads, James, Grogin, Norman, Curtis-Lake, Emma, Chevallard, Jacopo, Charlot, Stéphane, Finkelstein, Steven L., Koekemoer, Anton M., Ghavamian, Parviz, Rodrigues, Myriam, Hammer, François, Puech, Mathieu, Larson, Rebecca L., Christensen, Lise, Cimatti, Andrea, Ferreras, Ignacio, Gardner, Jonathan P., Gronwall, Caryl, Hathi, Nimish P., Joshi, Bhavin, Kuntschner, Harald, Meurer, Gerhardt R., O'Connell, Robert W., Oestlin, Goeran, Pasquali, Anna, Pharo, John, Straughn, Amber N., Walsh, Jeremy R., Watson, Darach, Windhorst, Rogier A., Zakamska, Nadia L., Ryan, Russell, Finkelstein, Steven, Koekemoer, Anton, Larson, Rebecca, Gardner, Jonathan, Hathi, Nimish, Meurer, Gerhardt, O’Connell, Robert, Straughn, Amber, Walsh, Jeremy, Windhorst, Rogier, Zakamska, Nadia, HE Space Operations BV for ESA/ESTEC, Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Galaxies, Etoiles, Physique, Instrumentation (GEPI), 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 Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Dark Cosmology Centre (DARK), Niels Bohr Institute [Copenhagen] (NBI), Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU)-Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), 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), European Southern Observatory (ESO), Space Telescope Science Institute (STSci), Pirzkal, Norbert, Rothberg, Barry, Ryan, Russell E., Malhotra, Sangeeta, Rhoads, Jame, Grogin, Norman, Curtis-Lake, Emma, Chevallard, Jacopo, Charlot, Stephane, Finkelstein, Steven L., Koekemoer, Anton M., Ghavamian, Parviz, Rodrigues, Myriam, Hammer, Francoi, Puech, Mathieu, Larson, Rebecca L., Christensen, Lise, Cimatti, Andrea, Ferreras, Ignacio, Gardner, Jonathan P., Gronwall, Caryl, Hathi, Nimish P., Joshi, Bhavin, Kuntschner, Harald, Meurer, Gerhardt R., O'Connell, Robert W., Oestlin, Goeran, Pasquali, Anna, Pharo, John, Straughn, Amber N., Walsh, Jeremy R., Watson, Darach, Windhorst, Rogier A., Zakamska, Nadia L, Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH)-Faculty of Science [Copenhagen], and University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH)

Subjects
Infrared, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Hubble space telescope, 0103 physical sciences, Emission spectrum, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, [PHYS]Physics [physics], 010308 nuclear & particles physics, Star formation, Astronomy and Astrophysics, Astronomy and Astrophysic, Wide field, Astrophysics - Astrophysics of Galaxies, methods: data analysis, Galaxy, Redshift, Grism, galaxies: distances and redshift, Space and Planetary Science, galaxies: star formation, Astrophysics of Galaxies (astro-ph.GA), galaxies: structure, galaxies: distances and redshifts, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], methods: data analysi
Abstract

We present the results from the application of a two-dimensional emission line detection method, EMission-line two-Dimensional (EM2D), to the near-infrared G102 grism observations obtained with the Wide-Field Camera 3 (WFC3) as part of the Cycle 22 {\em Hubble Space Telescope} Treasury Program: the Faint Infrared Grism Survey (FIGS). Using the EM2D method, we have assembled a catalog of emission line galaxies (ELGs) with resolved star formation from each of the four FIGS fields. Not only can one better assess the global properties of ELGs, but the EM2D method allows for the analysis and an improved study of the individual emission-line region {\it within} each galaxy. This paper includes a description of the methodology, advantages, and the first results of the EM2D method applied to ELGs in FIGS. The advantage of 2D emission line measurements includes significant improvement of galaxy redshift measurements, approaching the level of accuracy seen in high-spectral-resolution data, but with greater efficiency; and the ability to identify and measure the properties of multiple sites of star-formation and over scales of $\sim$ 1 kpc within individual galaxies out to z $\sim$ 4. The EM2D method also significantly improves the reliability of high-redshift ($z\sim7$) Lyman-$\alpha$ detections. Coupled with the wide field of view and high efficiency of space-based grism observations, EM2D provides a noteworthy improvement on the physical parameters that can be extracted from grism observations., Comment: Accepted by ApJ

Published
2018
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3. FIGS: spectral fitting constraints on the star formation history of massive galaxies since the cosmic noon.

Author

Ferreras, Ignacio, Pasquali, Anna, Pirzkal, Nor, Pharo, John, Malhotra, Sangeeta, Rhoads, James, Hathi, Nimish, Windhorst, Rogier, Cimatti, Andrea, Christensen, Lise, Finkelstein, Steven L, Grogin, Norman, Joshi, Bhavin, Kim, Keunho, Koekemoer, Anton, O'Connell, Robert, Östlin, Göran, Rothberg, Barry, and Ryan, Russell

Subjects
STAR formation, MARKOV chain Monte Carlo, GALAXIES, MONTE Carlo method, AGE of stars, STELLAR mass, PHOTOSYNTHETICALLY active radiation (PAR)
Abstract

We constrain the stellar population properties of a sample of 52 massive galaxies – with stellar mass log (M s/M⊙) ≳ 10.5 – over the redshift range 0.5 < z < 2 by use of observer-frame optical and near-infrared slitless spectra from Hubble Space Telescope 's ACS and WFC3 grisms. The deep exposures (∼100 ks) allow us to target individual spectra of massive galaxies to F160W = 22.5 AB. Our spectral fitting approach uses a set of six base models adapted to the redshift and spectral resolution of each observation, and fits the weights of the base models, including potential dust attenuation, via a Markov Chain Monte Carlo method. Our sample comprises a mixed distribution of quiescent (19) and star-forming galaxies (33). We quantify the width of the age distribution (Δ t) that is found to dominate the variance of the retrieved parameters according to principal component analysis. The population parameters follow the expected trend towards older ages with increasing mass, and Δ t appears to weakly anticorrelate with stellar mass, suggesting a more efficient star formation at the massive end. As expected, the redshift dependence of the relative stellar age (measured in units of the age of the Universe at the source) in the quiescent sample rejects the hypothesis of a single burst (aka monolithic collapse). Radial colour gradients within each galaxy are also explored, finding a wider scatter in the star-forming subsample, but no conclusive trend with respect to the population parameters. [ABSTRACT FROM AUTHOR]

Published
2019
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