8 research outputs found
The Grism lens-amplified survey from space (GLASS). VIII. The influence of the cluster properties on Halpha emitter galaxies at 0.3<z<0.7
Exploiting the data of the Grism Lens-Amplified Survey from Space (GLASS), we
characterize the spatial distribution of star formation in 76 high star forming
galaxies in 10 clusters at 0.3< z <0.7. All these galaxies are likely
restricted to first infall. In a companion paper we contrast the properties of
field and cluster galaxies, whereas here we correlate the properties of
H{\alpha} emitters to a number of tracers of the cluster environment to
investigate its role in driving galaxy transformations. H{\alpha} emitters are
found in the clusters out to 0.5 virial radii, the maximum radius covered by
GLASS. The peak of the H{\alpha} emission is offset with respect to the peak of
the UV-continuum. We decompose this offsets into a radial and tangential
component. The radial compo- nent points away from the cluster center in 60% of
the cases, with 95% confidence. The decompositions agree with cosmological
simulations, i.e. the H{\alpha} emission offset correlates with galaxy velocity
and ram-pressure stripping signatures. Trends between H{\alpha} emitter
properties and surface mass density distributions and X-ray emissions emerge
only for unrelaxed clusters. The lack of strong correlations with the global
environment does not allow us to identify a unique environmental effect
originating from the cluster center. In contrast, correla- tions between
H{\alpha} morphology and local number density emerge. We conclude that local
effects, uncorrelated to the cluster-centric radius, play a more important role
in shaping galaxy properties.Comment: ApJ in press (16 pages, 8 figures
The Grism Lens-Amplified Survey from Space (GLASS). VII. The Diversity of the Distribution of Star Formation in Cluster and Field Galaxies at 0.3 less than or equal to z less than or equal to 0.7
Exploiting the slitless spectroscopy taken as part of the Grism Lens-Amplified Survey from Space (GLASS), we present an extended analysis of the spatial distribution of star formation in 76 galaxies in 10 clusters at 0.3\lt z\lt 0.7. We use 85 foreground and background galaxies in the same redshift range as a field sample. The samples are well matched in stellar mass (108-1011 {M}☉ ) and star formation rate (0.5-50 {M}☉ {{yr}}-1). We visually classify galaxies in terms of broad band morphology, Hα morphology, and likely physical process acting on the galaxy. Most Hα emitters have a spiral morphology (41% ± 8% in clusters, 51% ± 8% in the field), followed by mergers/interactions (28% ± 8%, 31% ± 7%, respectively) and early-type galaxies (remarkably as high as 29% ± 8% in clusters and 15% ± 6% in the field). A diversity of Hα morphologies is detected, suggesting a diversity of physical processes. In clusters, 30% ± 8% of the galaxies present a regular morphology, mostly consistent with star formation diffused uniformly across the stellar population (mostly in the disk component, when present). The second most common morphology (28% ± 8%) is asymmetric/jellyfish, consistent with ram-pressure stripping or other non-gravitational processes in 18% ± 8% of the cases. Ram-pressure stripping appears significantly less prominent in the field (2% ± 2%), where the most common morphology/mechanism appears to be consistent with minor gas-rich mergers or clump accretion. This work demonstrates that while environment-specific mechanisms affect galaxy evolution at this redshift, they are diverse and their effects are subtle. A full understanding of this complexity requires larger samples and detailed and spatially resolved physical models
A Candidate Galaxy Strongly Lensed into a Spatially Resolved Arc
The most distant galaxies known are at z~10-11, observed 400-500 Myr after
the Big Bang. The few z~10-11 candidates discovered to date have been
exceptionally small- barely resolved, if at all, by the Hubble Space Telescope.
Here we present the discovery of SPT0615-JD, a fortuitous z~10
(z_phot=9.9+/-0.6) galaxy candidate stretched into an arc over ~2.5" by the
effects of strong gravitational lensing. Discovered in the Reionization Lensing
Cluster Survey (RELICS) Hubble Treasury program and companion S-RELICS Spitzer
program, this candidate has a lensed H-band magnitude of 25.7+/-0.1 AB mag.
With a magnification of \mu~4-7 estimated from our lens models, the de-lensed
intrinsic magnitude is 27.6+/-0.3 AB mag, and the half-light radius is r_e<0.8
kpc, both consistent with other z>9 candidates. The inferred stellar mass (log
[M* /M_Sun]=9.7^{+0.7}_{-0.5}) and star formation rate (\log [SFR/M_Sun
yr^{-1}]=1.3^{+0.2}_{-0.3}) indicate that this candidate is a typical
star-forming galaxy on the z>6 SFR-M* relation. We note that three independent
lens models predict two counterimages, at least one of which should be of a
similar magnitude to the arc, but these counterimages are not yet detected.
Counterimages would not be expected if the arc were at lower redshift. However,
the only spectral energy distributions capable of fitting the Hubble and
Spitzer photometry well at lower redshifts require unphysical combinations of
z~2 galaxy properties. The unprecedented lensed size of this z~10 candidate
offers the potential for the James Webb Space Telescope to study the geometric
and kinematic properties of a galaxy observed 500 Myr after the Big Bang.Comment: 7 pages, 4 figures. Submitted to ApJ Letter
Constraints on the Self‐Interaction Cross Section of Dark Matter from Numerical Simulations of the Merging Galaxy Cluster 1E 0657−56
The Grism Lens-Amplified Survey from Space (GLASS). VIII. The Influence of the Cluster Properties on H α
THE GRISM LENS-AMPLIFIED SURVEY FROM SPACE (GLASS). VII. THE DIVERSITY OF THE DISTRIBUTION OF STAR FORMATION IN CLUSTER AND FIELD GALAXIES AT 0.3 ≤ z
Exploiting the slitless spectroscopy taken as part of the Grism
Lens-Amplified Survey from Space (GLASS), we present an extended analysis of
the spatial distribution of star formation in 76 galaxies in 10 clusters at
0.3< z <0.7. We use 85 foreground and background galaxies in the same redshift
range as a field sample. The samples are well matched in stellar mass
(10^8-10^11 M_sun) and star formation rate (0.5-50 M_sun/yr). We visually
classify galaxies in terms of broad-band morphology, Halpha morphology and
likely physical process acting on the galaxy. Most Halpha emitters have a
spiral morphology (41+/-8% in clusters, 51+/-8% in the field), followed by
mergers/interactions (28+/-8%, 31+/-7%, respectively) and early-type galaxies
(remarkably as high as 29+/-8% in clusters and 15+/-6% in the field). A
diversity of Halpha morphologies is detected, suggesting a diversity of
physical processes. In clusters, 30+/-8% of the galaxies present a regular
morphology, mostly consistent with star formation diffused uniformly across the
stellar population (mostly in the disk component, when present). The second
most common morphology (28+/-8%) is asymmetric/jellyfish, consistent with ram
pressure stripping or other non-gravitational processes in 18+/-8% of the
cases. Ram pressure stripping appears significantly less prominent in the field
(2+/-2%), where the most common morphology/mechanism appears to be consistent
with minor gas rich mergers or clump accretion. This work demonstrates that
while environment specific mechanisms affect galaxy evolution at this redshift,
they are diverse and their effects subtle. A full understanding of this
complexity requires larger samples and detailed and spatially resolved physical
models.Comment: ApJ in press (22 pages, 21 figures