A5075295558- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Spectroscopy and Laser Applications
- Scientific Research and Discoveries
- Laser Design and Applications
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
University of Chicago
2019-2023
Brera Astronomical Observatory
2014-2023
University of Insubria
2014-2016
National Institute for Astrophysics
2014
We present the first estimate of age, stellar metallicity and chemical abundance ratios, for an individual early-type galaxy at high-redshift (z = 1.426) in COSMOS field. Our analysis is based on observations obtained with X-Shooter instrument VLT, which cover visual near infrared spectrum high (R >5000) spectral resolution. measure values several absorptions tracing species, particular Magnesium Iron, besides determining age-sensitive D4000 break. compare measured indices to population...
Aims. There are two aims to our analysis. On the one hand we interested in addressing whether a sample of morphologically selected early-type galaxies (ETGs) differs from passive terms galaxy statistics. other study how relative abundance galaxies, number density, and, stellar mass density for different morphological types change over redshift range 0.6 ≤ z 2.5.
We present a spectroscopic analysis based on measurements of two mainly age-dependent spectrophotometric indices in the 4000A rest frame region, i.e. H+K(CaII) and Delta4000, for sample 15 early-type galaxies (ETGs) at 0.7 < z_{spec} 1.1, morphologically selected GOODS-South field. Ages derived from different by means comparison with stellar population synthesis models, are not consistent each other least nine (60 per cent sample), while remaining six galaxies, ages their global spectral...
Context. We studied the size–surface brightness and size–mass relations of a sample 16 cluster elliptical galaxies in mass range ~ 1010−2 × 1011 M⊙, which were morphologically selected RDCS J0848+4453 at z = 1.27.
[Abridged] We studied the size-surface brightness and size-mass relations of a sample 16 cluster elliptical galaxies in mass range 10^{10}-2x10^{11} M_sun which were morphologically selected RDCS J0848+4453 at z=1.27. Our aim is to assess whether they have completed their growth redshift or significant and/or size can must take place until z=0 order understand clusters follow observed evolution passive galaxies. To compare our data with local universe we considered Kormendy relation derived...
We analyse publicly available, individual spectra of four, massive ($M>10^{11}M_{\odot}$) early-type galaxies with redshifts in the range 1.4 < z 2 to determine their stellar content, extending our previous work up z~2. The wide wavelength VLT/X-Shooter spectroscopic data UV-Optical-NIR arms along availability spectro-photometry allows us explore different techniques obtain population properties, namely through age/metallicity sensitive spectral indices, full fitting and broad-band...
In this paper we investigate the mass assembly history of ultramassive (Mstar > 10^11Msun) dense (Sigma = Mstar/(2*pi*Re^2) 2500 Msun/pc^2) early-type galaxies (ETGs) over last 9 Gyr. We have traced evolution number density rho ETGs and compared their structural (effective radius Re stellar Mstar) dynamical (velocity dispersion sigma_e) parameters redshift range 0 < z 1.6. derived at 1.6 1 from MUNICS GOODS-South surveys, while used COSMOS SDSS spectroscopic surveys to probe intermediate...
Context. The upcoming new generation of optical spectrographs on four-meter-class telescopes, with their huge multiplexing capabilities, excellent spectral resolution, and unprecedented wavelength coverage, will provide invaluable information for reconstructing the history star formation in individual galaxies up to redshifts about 0.7. Aims. We aim at defining simple but robust meaningful physical parameters that can be used trace coexistence widely diverse stellar components: younger...
The evolution of galaxies is imprinted in their stellar populations. Several population properties massive early-type have been shown to correlate with intrinsic galaxy like the galaxy's central velocity dispersion, suggesting that stars formed an initial collapse gas (z~2). However, populations change as a function radius, and it not clear how local gradients individual are influenced by global environment. In this paper, we study eight radius. We use optical spectroscopy (~4000-8600 \r{A})...
The complexity of constraining the stellar initial mass function (IMF) in early-type galaxies cannot be overstated, given necessity both very high signal-to-noise (S/N) data and difficulty breaking strong degeneracies that occur among several population parameters including age, metallicity elemental abundances. With this paper, second a series, we present detailed analysis biases can when retrieving IMF shape by exploiting optical NIR sensitive spectral indices. As test case, here analyze...
Abstract The Hydra I cluster offers an excellent opportunity to study and compare the relic old stellar populations in core of its two brightest galaxies. In addition, differing kinematics galaxies allows a test local validity general scaling relations. this work, we present direct comparison employing full spectral fitting new high-quality long-slit optical near-infrared spectroscopic data. We retrieve age, metallicity, 19 elemental abundances out ∼12 kpc within each galaxy, as well Initial...
This paper aims at understanding if the normalization of stellar initial mass function (IMF) massive early-type galaxies (ETGs) varies with cosmic time and/or mean density Sigma (M*/2\pi Re^2). For this purpose we collected a sample 18 dense (Sigma>2500 M_sun/pc^2) ETGs 1.2<z<1.6 available velocity dispersion sigma_e. We have constrained their mass-normalization by comparing true masses (M_true) derived through virial theorem, hence IMF independent, those inferred fit photometry assuming...
Abstract Recent studies of early-type galaxies have suggested that the initial mass function (IMF) slope is bottom-heavy; is, they contain a larger fraction low-mass stars than Milky Way. However, measurements IMF remain challenging in unresolved because features their observed spectra are sensitive to number factors, including stellar age, metallicity, and elemental abundances, addition IMF. In this paper, we use new high signal-to-noise IMACS (Magellan) study elliptical shell galaxy NGC...
We present a high signal-to-noise ratio (S/N > 10) medium-resolution (R = 2000) Large Binocular Telescope/LUCIFER spectrum of the early-type galaxy (ETG) S2F1-142 at z ≃ 1.4. By means CaT line 8662 Å, we measured its redshift 1.386 ± 0.001 and estimated velocity dispersion |$\sigma _{v}=340^{-60}_{+120}$| km s−1. Its corresponding virial mass is 3.9 × 1011 M⊙, compatible with stellar estimates obtained assuming initial functions (IMFs) less dwarf rich than Salpeter one. compact Re 3.1 0.2...
We present a high signal to noise (S/N$>$10) medium resolution (R=2000) LBT-LUCIFER spectrum of the early-type galaxy (ETG) S2F1-142 at $z\simeq1.4$. By means CaT line $8662$ Å, we measured its redshift $z=1.386\pm 0.001$ and estimated velocity dispersion $σ_{v}=340 ^{-60}_{+120}$ km/s. Its corresponding virial mass is 3.9$\times10^{11}$ M$_\odot$, compatible with stellar estimates obtained assuming Initial Mass Functions (IMFs) less dwarf rich than Salpeter one. compact...
The Hydra I cluster offers an excellent opportunity to study and compare the relic old stellar populations in core of its two brightest galaxies. In addition, differing kinematics galaxies allows a test local validity general scaling relations. this work we present direct comparison employing full spectral fitting new high-quality long-slit optical NIR spectroscopic data. We retrieve age, metallicity 19 elemental abundances out about 12 kpc within each galaxy, as well IMF their central...