11 research outputs found
The ALPINE-ALMA [C ii] Survey: Size of Individual Star-forming Galaxies at z = 4-6 and Their Extended Halo Structure
We present the physical extent of [CII] 158um line-emitting gas from 46
star-forming galaxies at z=4-6 from the ALMA Large Program to INvestigate CII
at Early Times (ALPINE). Using exponential profile fits, we measure the
effective radius of the [CII] line (r_e,[CII]) for individual galaxies and
compare them with the rest-frame ultra-violet (UV) continuum (r_e,UV) from
Hubble Space Telescope images. The effective radius r_e,[CII] exceeds r_e,UV by
factors of ~2-3 and the ratio of r_e,[CII]/r_e,UV increases as a function of
M_star. We do not find strong evidence that [CII] line, the rest-frame UV, and
FIR continuum are always displaced over ~ 1-kpc scale from each other. We
identify 30% of isolated ALPINE sources as having an extended [CII] component
over 10-kpc scales detected at 4.1-10.9 beyond the size of
rest-frame UV and far-infrared (FIR) continuum. One object has tentative
rotating features up to ~10-kpc, where the 3D model fit shows the rotating
[CII]-gas disk spread over 4 times larger than the rest-frame UV-emitting
region. Galaxies with the extended [CII] line structure have high
star-formation rate (SFR), stellar mass (M_star), low Lya equivalent-width, and
more blue-shifted (red-shifted) rest-frame UV metal absorption (Lya line), as
compared to galaxies without such extended [CII] structures. Although we cannot
rule out the possibility that a selection bias towards luminous objects may be
responsible for such trends, the star-formation driven outflow also explains
all these trends. Deeper observations are essential to test whether the
extended [CII] line structures are ubiquitous to high-z star-forming galaxies.ERC
STF
The ALPINE-ALMA [CII] survey: Dust attenuation properties and obscured star formation at z âŒ4.4-5.8
We present dust attenuation properties of spectroscopically confirmed star
forming galaxies on the main sequence at redshift ~4.4-5.8. Our analyses are
based on the far infrared continuum observations of 118 galaxies at rest-frame
obtained with the ALMA large program ALPINE. We study the
connection between the UV spectral slope (), stellar mass (),
and infrared excess (IRX). Twenty-three galaxies are
individually detected in the continuum at significance. We
perform a stacking analysis using both detections and non-detections to study
the average dust attenuation properties at z~4.4-5.8. The individual detections
and stacks show that the IRX- relation at z~5 is consistent with a
steeper dust attenuation curve than typically found at lower redshifts (z<4).
The attenuation curve is similar to or even steeper than that of the extinction
curve of the Small Magellanic Cloud (SMC). This systematic change of the
IRX- relation as a function of redshift suggests an evolution of dust
attenuation properties at . Similarly, we find that our galaxies have
lower IRX values up to 1 dex on average at fixed mass compared to previously
studied IRX- relations at , albeit with significant
scatter. This implies a lower obscured fraction of star-formation than at lower
redshifts. Our results suggest that dust properties of UV-selected star forming
galaxies at are characterised by (i) a steeper attenuation curve
than at , and (ii) a rapidly decreasing dust obscured fraction of
star formation as a function of redshift. Nevertheless, even among this
UV-selected sample, massive galaxies () at z~5-6
already exhibit an obscured fraction of star formation of ,
indicating a rapid build-up of dust during the epoch of reionization.STFC
ER
Genomic Targets of Brachyury (T) in Differentiating Mouse Embryonic Stem Cells
The T-box transcription factor Brachyury (T) is essential for formation of the posterior mesoderm and the notochord in vertebrate embryos. Work in the frog and the zebrafish has identified some direct genomic targets of Brachyury, but little is known about Brachyury targets in the mouse.Here we use chromatin immunoprecipitation and mouse promoter microarrays to identify targets of Brachyury in embryoid bodies formed from differentiating mouse ES cells. The targets we identify are enriched for sequence-specific DNA binding proteins and include components of signal transduction pathways that direct cell fate in the primitive streak and tailbud of the early embryo. Expression of some of these targets, such as Axin2, Fgf8 and Wnt3a, is down regulated in Brachyury mutant embryos and we demonstrate that they are also Brachyury targets in the human. Surprisingly, we do not observe enrichment of the canonical T-domain DNA binding sequence 5'-TCACACCT-3' in the vicinity of most Brachyury target genes. Rather, we have identified an (AC)(n) repeat sequence, which is conserved in the rat but not in human, zebrafish or Xenopus. We do not understand the significance of this sequence, but speculate that it enhances transcription factor binding in the regulatory regions of Brachyury target genes in rodents.Our work identifies the genomic targets of a key regulator of mesoderm formation in the early mouse embryo, thereby providing insights into the Brachyury-driven genetic regulatory network and allowing us to compare the function of Brachyury in different species
NK-cell-dependent killing of colon carcinoma cells is mediated by natural cytotoxicity receptors (NCRs) and stimulated by parvovirus infection of target cells
The ALPINE-ALMA [C II] survey: A triple merger at z ⌠4.56
We report the detection of [CII]158um emission from a system of three
closely-separated sources in the COSMOS field at z~4.56, as part of the ALMA
Large Program to INvestigate CII at Early times (ALPINE). The two dominant
sources are closely associated, both spatially (1.6"~11kpc) and in velocity
(~100km/s), while the third source is slightly more distant (2.8"~18kpc,
~300km/s). The second strongest source features a slight velocity gradient,
while no significant velocity gradient is seen in the other two sources. Using
the observed [CII] luminosities, we derive a total
log(SFR_[CII]/[Msol/year])=2.8+/-0.2, which may be split into contributions of
59%, 31%, and 10% from the central, east, and west sources, respectively.
Comparison of these [CII] detections to recent zoom-in cosmological simulations
suggests an ongoing major merger. We are thus witnessing a system in a major
phase of mass build-up by merging, including an on-going major merger and an
upcoming minor merger, which is expected to end up in a single massive galaxy
by z~2.5.ERC Advanced Grant 695671 âQUENCH
The ALPINE-ALMA [C ii] Survey: Multiwavelength Ancillary Data and Basic Physical Measurements
We present the ancillary data and basic physical measurements for the galaxies in the ALMA Large Program to Investigate C+ at Early Times (ALPINE) survey-the first large multiwavelength survey that aims at characterizing the gas and dust properties of 118 main-sequence galaxies at redshifts 4.4 z < 5.9 via the measurement of emission at (64% at >3.5 sigma) and the surrounding far-infrared continuum in conjunction with a wealth of optical and near-infrared data. We outline in detail the spectroscopic data and selection of the galaxies as well as the ground- and space-based imaging products. In addition, we provide several basic measurements including stellar masses, star formation rates (SFR), rest-frame ultra-violet (UV) luminosities, UV continuum slopes (beta), and absorption line redshifts, as well as H alpha emission derived from Spitzer colors. We find that the ALPINE sample is representative of the 4 z < 6 galaxy population selected by photometric methods and only slightly biased toward bluer colors (Delta beta similar to 0.2). Using [] as tracer of the systemic redshift (confirmed for one galaxy at z = 4.5 out of 118 for which we obtained optical [lambda 3727A emission), we confirm redshifted Ly alpha emission and blueshifted absorption lines similar to findings at lower redshifts. By stacking the rest-frame UV spectra in the [] rest frame, we find that the absorption lines in galaxies with high specific SFR are more blueshifted, which could be indicative of stronger winds and outflows
COSMOS2020: A Panchromatic View of the Universe to z ⌠10 from Two Complementary Catalogs
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 have been collected in the COSMOS field. This paper describes the collection, processing, and analysis of these new imaging data to produce a new reference photometric redshift catalog. Source detection and multiwavelength photometry are performed for 1.7 million sources across the 2 deg2 of the COSMOS field, âŒ966,000 of which are measured with all available broadband 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 < 21 sources have subpercent photometric redshift accuracy and even the faintest sources at 25 < i < 27 reach a precision of 5%. Finally, these results are discussed in the context of previous, current, and future surveys in the COSMOS field. Compared to COSMOS2015, it reaches the same photometric redshift precision at almost one magnitude deeper. Both photometric catalogs and their photometric redshift solutions and physical parameters will be made available through the usual astronomical archive systems (ESO Phase 3, IPAC-IRSA, and CDS).</jats:p