310 research outputs found
The Grism Lens-Amplified Survey from Space (GLASS). XII. Spatially Resolved Galaxy Star Formation Histories and True Evolutionary Paths at z > 1
Modern data empower observers to describe galaxies as the spatially and
biographically complex objects they are. We illustrate this through case
studies of four, systems based on deep, spatially resolved, 17-band
+ G102 + G141 Hubble Space Telescope grism spectrophotometry. Using full
spectrum rest-UV/-optical continuum fitting, we characterize these galaxies'
observed kpc-scale structures and star formation rates (SFRs) and
reconstruct their history over the age of the universe. The sample's
diversity---passive to vigorously starforming; stellar masses to ---enables us to draw spatio-temporal inferences
relevant to key areas of parameter space (Milky Way- to super-Andromeda-mass
progenitors). Specifically, we find signs that bulge mass-fractions () and
SF history shapes/spatial uniformity are linked, such that higher s
correlate with "inside-out growth" and central specific SFRs that peaked above
the global average for all starforming galaxies at that epoch. Conversely, the
system with the lowest had a flat, spatially uniform SFH with normal peak
activity. Both findings are consistent with models positing a feedback-driven
connection between bulge formation and the switch from rising to falling SFRs
("quenching"). While sample size forces this conclusion to remain tentative,
this work provides a proof-of-concept for future efforts to refine or refute
it: JWST, WFIRST, and the 30-m class telescopes will routinely produce data
amenable to this and more sophisticated analyses. These samples---spanning
representative mass, redshift, SFR, and environmental regimes---will be ripe
for converting into thousands of sub-galactic-scale empirical windows on what
individual systems actually looked like in the past, ushering in a new dialog
between observation and theory.Comment: 18 pp, 15 figs, 3 tables (main text); 5 pp, 5 figs, 1 table
(appendix); Submitted to AAS Journals 1 October 201
Probing dark matter substructure in the gravitational lens HE0435-1223 with the WFC3 grism
Strong gravitational lensing provides a powerful test of Cold Dark Matter
(CDM) as it enables the detection and mass measurement of low mass haloes even
if they do not contain baryons. Compact lensed sources such as Active Galactic
Nuclei (AGN) are particularly sensitive to perturbing subhalos, but their use
as a test of CDM has been limited by the small number of systems which have
significant radio emission which is extended enough avoid significant lensing
by stars in the plane of the lens galaxy, and red enough to be minimally
affected by differential dust extinction. Narrow-line emission is a promising
alternative as it is also extended and, unlike radio, detectable in virtually
all optically selected AGN lenses. We present first results from a WFC3 grism
narrow-line survey of lensed quasars, for the quadruply lensed AGN HE0435-1223.
Using a forward modelling pipeline which enables us to robustly account for
spatial blending, we measure the [OIII] 5007 \AA~ flux ratios of the four
images. We find that the [OIII] fluxes and positions are well fit by a simple
smooth mass model for the main lens. Our data rule out a NFW perturber projected within 1\farcs0 (0\farcs1)
arcseconds of each of the lensed images, where is the perturber mass
within its central 600 pc. The non-detection is broadly consistent with the
expectations of CDM for a single system. The sensitivity achieved
demonstrates that powerful limits on the nature of dark matter can be obtained
with the analysis of narrow-line lenses.Comment: Accepted for publication in MNRAS, 15 pages, 8 figure
The story of supernova 'Refsdal' told by MUSE
We present MUSE observations in the core of the HFF galaxy cluster MACS
J1149.5+2223, where the first magnified and spatially-resolved multiple images
of SN 'Refsdal' at redshift 1.489 were detected. Thanks to a DDT program with
the VLT and the extraordinary efficiency of MUSE, we measure 117 secure
redshifts with just 4.8 hours of total integration time on a single target
pointing. We spectroscopically confirm 68 galaxy cluster members, with redshift
values ranging from 0.5272 to 0.5660, and 18 multiple images belonging to 7
background, lensed sources distributed in redshifts between 1.240 and 3.703.
Starting from the combination of our catalog with those obtained from extensive
spectroscopic and photometric campaigns using the HST, we select a sample of
300 (164 spectroscopic and 136 photometric) cluster members, within
approximately 500 kpc from the BCG, and a set of 88 reliable multiple images
associated to 10 different background source galaxies and 18 distinct knots in
the spiral galaxy hosting SN 'Refsdal'. We exploit this valuable information to
build 6 detailed strong lensing models, the best of which reproduces the
observed positions of the multiple images with a rms offset of only 0.26". We
use these models to quantify the statistical and systematic errors on the
predicted values of magnification and time delay of the next emerging image of
SN 'Refsdal'. We find that its peak luminosity should should occur between
March and June 2016, and should be approximately 20% fainter than the dimmest
(S4) of the previously detected images but above the detection limit of the
planned HST/WFC3 follow-up. We present our two-dimensional reconstruction of
the cluster mass density distribution and of the SN 'Refsdal' host galaxy
surface brightness distribution. We outline the roadmap towards even better
strong lensing models with a synergetic MUSE and HST effort.Comment: 21 pages, 9 figures, 6 tables; accepted for publication in the
Astrophysical Journal - extra information on data analysis added, all model
predictions and results unchange
The Grism Lens-Amplified Survey from Space (GLASS). I. Survey overview and first data release
We give an overview of the Grism Lens Amplified Survey from Space (GLASS), a
large Hubble Space Telescope program aimed at obtaining grism spectroscopy of
the fields of ten massive clusters of galaxies at redshift z=0.308-0.686,
including the Hubble Frontier Fields (HFF). The Wide Field Camera 3 yields near
infrared spectra of the cluster cores, covering the wavelength range
0.81-1.69mum through grisms G102 and G141, while the Advanced Camera for
Surveys in parallel mode provides G800L spectra of the infall regions of the
clusters. The WFC3 spectra are taken at two almost orthogonal position angles
in order to minimize the effects of confusion. After summarizing the scientific
drivers of GLASS, we describe the sample selection as well as the observing
strategy and data processing pipeline. We then utilize MACSJ0717.5+3745, a HFF
cluster and the first one observed by GLASS, to illustrate the data quality and
the high-level data products. Each spectrum brighter than H_AB=23 is visually
inspected by at least two co-authors and a redshift is measured when sufficient
information is present in the spectra. Furthermore, we conducted a thorough
search for emission lines through all the GLASS WFC3 spectra with the aim of
measuring redshifts for sources with continuum fainter than H_AB=23. We provide
a catalog of 139 emission-line based spectroscopic redshifts for extragalactic
sources, including three new redshifts of multiple image systems (one probable,
two tentative). In addition to the data itself we also release software tools
that are helpful to navigate the data.Comment: ApJ in press. GLASS data available at
https://archive.stsci.edu/prepds/glass/ . More info on GLASS available at
http://glass.physics.ucsb.edu
The Grism Lens-amplified Survey from Space (GLASS). X. Sub-kiloparsec Resolution Gas-phase Metallicity Maps at Cosmic Noon behind the Hubble Frontier Fields Cluster MACS1149.6+2223
We combine deep Hubble Space Telescope grism spectroscopy with a new Bayesian method to derive maps of gas-phase metallicity for 10 star-forming galaxies at high redshift (). Exploiting lensing magnification by the foreground cluster MACS1149.6+2223, we reach sub-kiloparsec spatial resolution and push the limit of stellar mass associated with such high-z spatially resolved measurements below for the first time. Our maps exhibit diverse morphologies, indicative of various effects such as efficient radial mixing from tidal torques, rapid accretion of low-metallicity gas, and other physical processes that can affect the gas and metallicity distributions in individual galaxies. Based upon an exhaustive sample of all existing sub-kiloparesec resolution metallicity gradient measurements at high z, we find that predictions given by analytical chemical evolution models assuming a relatively extended star-formation profile in the early disk-formation phase can explain the majority of observed metallicity gradients, without involving galactic feedback or radial outflows. We observe a tentative correlation between stellar mass and metallicity gradients, consistent with the "downsizing" galaxy formation picture that more massive galaxies are more evolved into a later phase of disk growth, where they experience more coherent mass assembly at all radii and thus show shallower metallicity gradients. In addition to the spatially resolved analysis, we compile a sample of homogeneously cross-calibrated integrated metallicity measurements spanning three orders of magnitude in stellar mass at z ~ 1.8. We use this sample to study the mass–metallicity relation (MZR) and find that the slope of the observed MZR can rule out the momentum-driven wind model at a 3σ confidence level
The Grism Lens-amplified Survey from Space (GLASS). X. Sub-kiloparsec Resolution Gas-phase Metallicity Maps at Cosmic Noon behind the Hubble Frontier Fields Cluster MACS1149.6+2223
We combine deep Hubble Space Telescope grism spectroscopy with a new Bayesian method to derive maps of gas-phase metallicity for 10 star-forming galaxies at high redshift (). Exploiting lensing magnification by the foreground cluster MACS1149.6+2223, we reach sub-kiloparsec spatial resolution and push the limit of stellar mass associated with such high-z spatially resolved measurements below for the first time. Our maps exhibit diverse morphologies, indicative of various effects such as efficient radial mixing from tidal torques, rapid accretion of low-metallicity gas, and other physical processes that can affect the gas and metallicity distributions in individual galaxies. Based upon an exhaustive sample of all existing sub-kiloparesec resolution metallicity gradient measurements at high z, we find that predictions given by analytical chemical evolution models assuming a relatively extended star-formation profile in the early disk-formation phase can explain the majority of observed metallicity gradients, without involving galactic feedback or radial outflows. We observe a tentative correlation between stellar mass and metallicity gradients, consistent with the "downsizing" galaxy formation picture that more massive galaxies are more evolved into a later phase of disk growth, where they experience more coherent mass assembly at all radii and thus show shallower metallicity gradients. In addition to the spatially resolved analysis, we compile a sample of homogeneously cross-calibrated integrated metallicity measurements spanning three orders of magnitude in stellar mass at z ~ 1.8. We use this sample to study the mass–metallicity relation (MZR) and find that the slope of the observed MZR can rule out the momentum-driven wind model at a 3σ confidence level
H0LiCOW - IX. Cosmographic analysis of the doubly imaged quasar SDSS 1206+4332 and a new measurement of the Hubble constant
We present a blind time-delay strong lensing (TDSL) cosmographic analysis of
the doubly imaged quasar SDSS 1206+4332. We combine the relative time delay
between the quasar images, Hubble Space Telescope imaging, the Keck stellar
velocity dispersion of the lensing galaxy, and wide-field photometric and
spectroscopic data of the field to constrain two angular diameter distance
relations. The combined analysis is performed by forward modelling the
individual data sets through a Bayesian hierarchical framework, and it is kept
blind until the very end to prevent experimenter bias. After unblinding, the
inferred distances imply a Hubble constant
kmsMpc, assuming a flat Lambda cold dark matter cosmology with
uniform prior on in [0.05, 0.5]. The precision of our
cosmographic measurement with the doubly imaged quasar SDSS 1206+4332 is
comparable with those of quadruply imaged quasars and opens the path to perform
on selected doubles the same analysis as anticipated for quads. Our analysis is
based on a completely independent lensing code than our previous three H0LiCOW
systems and the new measurement is fully consistent with those. We provide the
analysis scripts paired with the publicly available software to facilitate
independent analysis. The consistency between blind measurements with
independent codes provides an important sanity check on lens modelling
systematics. By combining the likelihoods of the four systems under the same
prior, we obtain kmsMpc. This
measurement is independent of the distance ladder and other cosmological
probes.Comment: 30 pages, 17 figures, MNRAS published likelihood available here:
http://shsuyu.github.io/H0LiCOW/site/notebooks/H0_from_lenses.html, all
modeling and analysis scripts available upon reques
The Lick AGN Monitoring Project 2011: Spectroscopic Campaign and Emission-Line Light Curves
In the Spring of 2011 we carried out a 2.5 month reverberation mapping
campaign using the 3 m Shane telescope at Lick Observatory, monitoring 15
low-redshift Seyfert 1 galaxies. This paper describes the observations,
reductions and measurements, and data products from the spectroscopic campaign.
The reduced spectra were fitted with a multicomponent model in order to isolate
the contributions of various continuum and emission-line components. We present
light curves of broad emission lines and the AGN continuum, and measurements of
the broad H-beta line widths in mean and root-mean square (rms) spectra. For
the most highly variable AGNs we also measured broad H-beta line widths and
velocity centroids from the nightly spectra. In four AGNs exhibiting the
highest variability amplitudes, we detect anticorrelations between broad H-beta
width and luminosity, demonstrating that the broad-line region "breathes" on
short timescales of days to weeks in response to continuum variations. We also
find that broad H-beta velocity centroids can undergo substantial changes in
response to continuum variations; in NGC 4593 the broad H-beta velocity shifted
by ~250 km/s over a one-month duration. This reverberation-induced velocity
shift effect is likely to contribute a significant source of confusion noise to
binary black hole searches that use multi-epoch quasar spectroscopy to detect
binary orbital motion. We also present results from simulations that examine
biases that can occur in measurement of broad-line widths from rms spectra due
to the contributions of continuum variations and photon-counting noise.Comment: 33 pages, 28 figures, accepted for publication in ApJ Supplement
Serie
The radio luminosity, black hole mass and Eddington ratio for quasars from the Sloan Digital Sky Survey
We investigate the \mbh- \sigma_* relation for radio-loud quasars with
redshift in Data Release 3 of the Sloan Digital Sky Survey (SDSS). The
sample consists of 3772 quasars with better model of H and \oiii lines
and available radio luminosity, including 306 radio-loud quasars, 3466
radio-quiet quasars with measured radio luminosity or upper-limit of radio
luminosity (181 radio-quiet quasars with measured radio luminosity). The virial
supermassive black hole mass (\mbh) is calculated from the broad \hb line, the
host stellar velocity dispersion () is traced by the core \oiii
gaseous velocity dispersion, and the radio luminosity and the radio loudness
are derived from the FIRST catalog. Our results are follows: (1) For
radio-quiet quasars, we confirm that there is no obvious deviation from the
\mbh- \sigma_* relation defined in inactive galaxies when \mbh uncertainties
and luminosity bias are concerned. (2) We find that radio-loud quasars deviate
much from the \mbh- \sigma_* relation respect to that for radio-quiet
quasars. This deviation is only partly due to the possible cosmology evolution
of the \mbh- \sigma_* relation and the luminosity bias. (3) The radio
luminosity is proportional to
\mbh^{1.28^{+0.23}_{-0.16}}(\lb/\ledd)^{1.29^{+0.31}_{-0.24}} for radio-quiet
quasars and \mbh^{3.10^{+0.60}_{-0.70}}(\lb/\ledd)^{4.18^{+1.40}_{-1.10}} for
radio-loud quasars. The weaker correlation of the radio luminosity dependence
upon the mass and the Eddington ratio for radio-loud quasars shows that other
physical effects would account for their radio luminosities, such as the black
hole spin.Comment: 15 pages, 8 figures, 2 tables, accepted for publication in ChJA
THE GRISM LENS-AMPLIFIED SURVEY FROM SPACE (GLASS). VI. COMPARING THE MASS AND LIGHT IN MACS J0416.1-2403 USING FRONTIER FIELD IMAGING AND GLASS SPECTROSCOPY
We present a strong and weak gravitational lens model of the galaxy cluster
MACSJ0416.1-2403, constrained using spectroscopy from the Grism Lens-Amplified
Survey from Space (GLASS) and Hubble Frontier Fields (HFF) imaging data. We
search for emission lines in known multiply imaged sources in the GLASS
spectra, obtaining secure spectroscopic redshifts of 31 multiple images
belonging to 16 distinct source galaxies. The GLASS spectra provide the first
spectroscopic measurements for 6 of the source galaxies. The weak lensing
signal is acquired from 884 galaxies in the F606W HFF image. By combining the
weak lensing constraints with 15 multiple image systems with spectroscopic
redshifts and 9 multiple image systems with photometric redshifts, we
reconstruct the gravitational potential of the cluster on an adaptive grid. The
resulting total mass density map is compared with a stellar mass density map
obtained from the deep Spitzer Frontier Fields imaging data to study the
relative distribution of stellar and total mass in the cluster. We find that
the projected stellar mass to total mass ratio, , varies
considerably with the stellar surface mass density. The mean projected stellar
mass to total mass ratio is
(stat.), but with a systematic error as large as , dominated by
the choice of the IMF. We find agreement with several recent measurements of
in massive cluster environments. The lensing maps of convergence,
shear, and magnification are made available to the broader community in the
standard HFF format.Comment: 48 pages, 45 figure
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