1,538 research outputs found
The rest-frame optical (900nm) galaxy luminosity function at z ~ 4-7: abundance matching points to limited evolution in the M_(STAR)/M_(HALO) ratio at z ⩾ 4
We present the first determination of the galaxy luminosity function (LF) at z ~ 4, 5, 6, and 7, in the rest-frame optical at λ_(res) ~ 900 nm (z' band). The rest-frame optical light traces the content in low-mass evolved stars (~stellar mass—M*), minimizing potential measurement biases for M*. Moreover, it is less affected by nebular line emission contamination and dust attenuation, is independent of stellar population models, and can be probed up to z ~ 8 through Spitzer/IRAC. Our analysis leverages the unique full-depth Spitzer/IRAC 3.6–8.0 μm data over the CANDELS/GOODS-N, CANDELS/GOODS-S, and COSMOS/UltraVISTA fields. We find that, at absolute magnitudes where M_z’ is fainter than ≳-23 mag, M_z’ linearly correlates with M_(UV, 1600). At brighter M_z’, M_(UV, 1600) presents a turnover, suggesting that the stellar mass-to-light ratio M*/L_(UV, 1600) could be characterized by a very broad range of values at high stellar masses. Median-stacking analyses recover an M*/L_z’ roughly independent on M_z’ for M_z’ ≳ -23 mag, but exponentially increasing at brighter magnitudes. We find that the evolution of the LF marginally prefers a pure luminosity evolution over a pure density evolution, with the characteristic luminosity decreasing by a factor of _5x between z ~ 4 and z ~ 7. Direct application of the recovered M*/L_z’ generates stellar mass functions consistent with average measurements from the literature. Measurements of the stellar-to-halo mass ratio at fixed cumulative number density show that it is roughly constant with redshift for M_h ≳ 10^(12) M⊙. This is also supported by the fact that the evolution of the LF at 4 ≾ z ≾ 7 can be accounted for by a rigid displacement in luminosity, corresponding to the evolution of the halo mass from abundance matching
Galaxy Stellar Mass Functions from z~10 to z~6 using the Deepest Spitzer/IRAC Data: No Significant Evolution in the Stellar-to-Halo Mass Ratio of Galaxies in the First Gyr of Cosmic Time
We present new stellar mass functions at , , ,
and, for the first time, , constructed from
Lyman-Break galaxies previously identified over the XDF/UDF, parallels and the
five CANDELS fields. Our study is distinctive due to (1) the much deeper
( hour) wide-area Spitzer/IRAC imaging at m and m from
the GOODS Re-ionization Era wide Area Treasury from Spitzer (GREATS) program
and (2) consideration of sources over a larger area than
previous HST+Spitzer studies. The Spitzer/IRAC data enable
rest-frame optical detections for an unprecedented of galaxies down to a
stellar mass limit of across all redshifts.
Schechter fits to our volume densities suggest a combined evolution in
characteristic mass and normalization factor between
and . The stellar mass density (SMD) increases by
in the Myr between and , with
indications of a steeper evolution between and , similar to
the previously-reported trend of the star-formation rate density. Strikingly,
abundance matching to the Bolshoi-Planck simulation indicates halo mass
densities evolving at approximately the same rate as the SMD between
and . Our results show that the stellar-to-halo mass ratios, a proxy
for the star-formation efficiency, do not change significantly over the huge
stellar mass build-up occurred from to , indicating that the
assembly of stellar mass closely mirrors the build-up in halo mass in the first
Gyr of cosmic history. JWST is poised to extend these results into the
"first galaxy" epoch at .Comment: Submitted to ApJ, comments welcom
Blue Rest-Frame UV-Optical Colors in z~8 Galaxies from GREATS: Very Young Stellar Populations at ~650 Myr of Cosmic Time
Deep rest-optical observations are required to accurately constrain the
stellar populations of galaxies. Due to significant limitations in the
availability of such data for statistically complete samples, observational
results have been limited to modest numbers of bright or lensed sources. To
revolutionize the present characterization of galaxies, we exploit the
ultradeep ( mag, ) Spitzer/IRAC m and m data,
probing the rest-frame optical at , over arcmin of the
GOODS fields from the recently completed GOODS Re-ionization Era wide-Area
Treasury from Spitzer (GREATS) program, combined with observations in the
CANDELS UDS and COSMOS fields. We stacked Lyman-Break
galaxies in four bins of UV luminosity ( to )
and study their and colors. We find young
ages ( Myr) for the three faintest stacks, inferred from their
blue mag colors, consistent with a negative Balmer
break. Meanwhile, the redder color seen in the brightest
stack is suggestive of slightly older ages. We explored the existence of a
correlation between the UV luminosity and age, and find either no trend or
fainter galaxies being younger. The stacked SEDs also exhibit very red
mag colors, indicative of intense [OIII]+H nebular
emission and SFR. The correspondingly high specific star-formation rates,
sSFRGyr, are consistent with recent determinations at similar
redshifts and higher luminosities, and support the co-evolution between the
sSFR and the specific halo mass accretion rate.Comment: Submitted to ApJ. Comments welcome. See Fig. 2 & 3 for the stacks,
Fig. 4 & 6 for the colors/age and Fig. 8 for the sSFR evolutio
The Evolution of Mass-size Relation for Lyman Break Galaxies From z=1 to z=7
For the first time, we study the evolution of the stellar mass-size relation
for star-forming galaxies from z ~ 4 to z ~ 7 from Hubble-WFC3/IR camera
observations of the HUDF and Early Release Science (ERS) field. The sizes are
measured by determining the best fit model to galaxy images in the rest-frame
2100 \AA \ with the stellar masses estimated from SED fitting to rest-frame
optical (from Spitzer/IRAC) and UV fluxes. We show that the stellar mass-size
relation of Lyman-break galaxies (LBGs) persists, at least to z ~ 5, and the
median size of LBGs at a given stellar mass increases towards lower redshifts.
For galaxies with stellar masses of 9.5<Log(M*/Msun)<10.4 sizes evolve as
. This evolution is very similar for galaxies with lower
stellar masses of 8.6<Log(M*/Msun)<9.5 which is , in agreement with simple theoretical galaxy formation
models at high z. Our results are consistent with previous measurements of the
LBGs mass-size relation at lower redshifts (z ~ 1-3).Comment: Accepted for publication in The Astrophysical Journal Letter
Analysis of the gastrin-releasing peptide receptor gene in Italian patients with autism spectrum disorders
The gastrin-releasing peptide receptor (GRPR) was implicated for the first time in the pathogenesis of Autism spectrum disorders (ASD) by Ishikawa-Brush et al. [Ishikawa-Brush et al. (1997): Hum Mol Genet 6: 1241-1250]. Since this original observation, only one association study [Marui et al. (2004): Brain Dev 26: 5-7] has further investigated, though unsuccessfully, the involvement of the GRPR gene in ASD. With the aim of contributing further information to this topic we have sequenced the entire coding region and the intron/exon junctions of the GRPR gene in 149 Italian autistic patients. The results of this study led to the identification of four novel point mutations, two of which, that is, C6S and L181F, involve amino acid changes identified in two patients with ASD and Rett syndrome, respectively. Both the leucine at position 181 and the cysteine at position 6 are strongly conserved in vertebrates. C6S and L181F mutant proteins were expressed in COS-7 and BALB/3T3 cells, but they did not affect either GRP's binding affinity or its potency for stimulating phospholipase C-mediated production of inositol 1,4,5-trisphosphate. In summary, our results do not provide support for a major role of the GRPR gene in ASD in the population of patients we have studied. However, there is a potential role of C6S and L181F mutations on GRPR function, and possibly in the pathogenesis of the autistic disorders in the two patient
Hubble Legacy Field GOODS-S Photometric Catalog
This manuscript describes the public release of the Hubble Legacy Fields (HLF) project photometric catalog for the extended GOODS-South region from the Hubble Space Telescope (HST) archival program AR-13252. The analysis is based on the version 2.0 HLF data release that now includes all ultraviolet (UV) imaging, combining three major UV surveys. The HLF data combines over a decade worth of 7475 exposures taken in 2635 orbits totaling 6.3 Ms with the HST Advanced Camera for Surveys Wide Field Channel (ACS/WFC) and the Wide Field Camera 3 (WFC3) UVIS/IR Channels in the greater GOODS-S extragalactic field, covering all major observational efforts (e.g., GOODS, GEMS, CANDELS, ERS, UVUDF, and many other programs; see Illingworth et al.). The HLF GOODS-S catalogs include photometry in 13 bandpasses from the UV (WFC3/UVIS F225W, F275W, and F336W filters), optical (ACS/WFC F435W, F606W, F775W, F814W and F850LP filters), to near-infrared (WFC3/IR F098M, F105W, F125W, F140W and F160W filters). Such a data set makes it possible to construct the spectral energy distributions (SEDs) of objects over a wide wavelength range from high-resolution mosaics that are largely contiguous. Here, we describe a photometric analysis of 186,474 objects in the HST imaging at wavelengths 0.2–1.6 μm. We detect objects from an ultra-deep image combining the PSF-homogenized and noise-equalized F850LP, F125W, F140W, and F160W images, including Gaia astrometric corrections. SEDs were determined by carefully taking the effects of the point-spread function in each observation into account. All of the data presented herein are available through the HLF website (https://archive.stsci.edu/prepds/hlf/)
The Hubble Legacy Field GOODS-S Photometric Catalog
This manuscript describes the public release of the Hubble Legacy Fields
(HLF) project photometric catalog for the extended GOODS-South region from the
Hubble Space Telescope (HST) archival program AR-13252. The analysis is based
on the version 2.0 HLF data release that now includes all ultraviolet (UV)
imaging, combining three major UV surveys. The HLF data combines over a decade
worth of 7475 exposures taken in 2635 orbits totaling 6.3 Msec with the HST
Advanced Camera for Surveys Wide Field Channel (ACS/WFC) and the Wide Field
Camera 3 (WFC3) UVIS/IR Channels in the greater GOODS-S extragalactic field,
covering all major observational efforts (e.g., GOODS, GEMS, CANDELS, ERS,
UVUDF and many other programs; see Illingworth et al 2019, in prep). The HLF
GOODS-S catalogs include photometry in 13 bandpasses from the UV (WFC3/UVIS
F225W, F275W and F336W filters), optical (ACS/WFC F435W, F606W, F775W, F814W
and F850LP filters), to near-infrared (WFC3/IR F098M, F105W, F125W, F140W and
F160W filters). Such a data set makes it possible to construct the spectral
energy distributions (SEDs) of objects over a wide wavelength range from high
resolution mosaics that are largely contiguous. Here, we describe a photometric
analysis of 186,474 objects in the HST imaging at wavelengths 0.2--1.6m.
We detect objects from an ultra-deep image combining the PSF-homogenized and
noise-equalized F850LP, F125W, F140W and F160W images, including Gaia
astrometric corrections. SEDs were determined by carefully taking the effects
of the point-spread function in each observation into account. All of the data
presented herein are available through the HLF website
(https://archive.stsci.edu/prepds/hlf/).Comment: Hubble Legacy Fields GOODS-S public data release available at
https://archive.stsci.edu/prepds/hlf/. Accepted for publication in ApJS (20
pages, 22 figures, 2 tables
The Physical Properties of Star-Forming Galaxies with Strong [O III] Lines at z=3.25
We present an analysis of physical properties of 34 [O III] emission-line
galaxies (ELGs) at z=3.2540.029 in the Extended Chandra Deep Field South
(ECDFS). These ELGs are selected from deep narrow H2S(1) and broad Ks imaging
of 383 arcmin obtained with CFHT/WIRCam. We construct spectral energy
distributions (SEDs) from U to Ks to derive the physical properties of ELGs.
These [O III] ELGs are identified as starburst galaxies with strong [O III]
lines of L([O III]) ~ 10 - 10 erg s, and have stellar
masses of M* ~ 10-10 M and star formation rates of ~
10-210 M yr. Our results show that 24% of our sample galaxies
are dusty with Av > 1 mag and EW(OIII) ~ 70-500 , which are often
missed in optically selected [O III] ELG samples. Their rest-frame UV and
optical morphologies from HST/ACS and HST/WFC3 deep imaging reveal that these
[O III] ELGs are mostly multiple-component systems (likely mergers) or compact.
And 20% of them are nearly invisible in the rest-frame UV owing to heavy dust
attenuation. Interestingly, we find that our samples reside in an overdensity
consisting of two components: one southeast (SE) with an overdensity factor of
~ 41 over a volume of 13 cMpc and the other
northwest (NW) with ~ 38 over a volume of 10 cMpc.
The two overdense substructures are expected to be virialized at z=0 with a
total mass of ~ 1.1 x 10 M and ~ 4.8 x 10 M, and
probably merge into a Coma-like galaxy cluster.Comment: 22 pages, 11 figures, 3 tables. Accepted for publication in Ap
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