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1131. HST NIR grism sp. of strong-lensing galaxy clusters
ID:
ivo://CDS.VizieR/J/ApJ/900/183
Title:
HST NIR grism sp. of strong-lensing galaxy clusters
Short Name:
J/ApJ/900/183
Date:
15 Feb 2022 11:31:32
Publisher:
CDS
Description:
We present the hitherto largest sample of gas-phase metallicity radial gradients measured at sub-kpc resolution in star-forming galaxies in the redshift range of 1.2<z<=2.3. These measurements are enabled by the synergy of slitless spectroscopy from the Hubble Space Telescope near-infrared channels and the lensing magnification from foreground galaxy clusters. Our sample consists of 76 galaxies with stellar mass ranging from 10^7^ to 10^10^M_{sun}, an instantaneous star formation rate in the range of [1,100]M_{sun}_/yr, and global metallicity [1/12,2] of solar. At a 2{sigma} confidence level, 15/76 galaxies in our sample show negative radial gradients, whereas 7/76 show inverted gradients. Combining ours and all other metallicity gradients obtained at a similar resolution currently available in the literature, we measure a negative mass dependence of {Delta}log(O/H)/{Delta}r[dex/kpc]=(-0.020+/-0.007)+(-0.016+/-0.008) log(M_*_/10^9.4^M_{sun}_), with the intrinsic scatter being {sigma}=0.060+/-0.006 over 4 orders of magnitude in stellar mass. Our result is consistent with strong feedback, not secular processes, being the primary governor of the chemostructural evolution of star-forming galaxies during the disk mass assembly at cosmic noon. We also find that the intrinsic scatter of metallicity gradients increases with decreasing stellar mass and increasing specific star formation rate. This increase in the intrinsic scatter is likely caused by the combined effect of cold-mode gas accretion and merger-induced starbursts, with the latter more predominant in the dwarf mass regime of M_*_<~10^9^M_{sun}_.
1132. HST NIR spectroscopy of ISCS z>1 galaxy clusters
ID:
ivo://CDS.VizieR/J/ApJ/779/137
Title:
HST NIR spectroscopy of ISCS z>1 galaxy clusters
Short Name:
J/ApJ/779/137
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present Hubble Space Telescope near-IR spectroscopy for 18 galaxy clusters at 1.0<z<1.5 in the IRAC Shallow Cluster Survey (ISCS). We use Wide Field Camera 3 grism data to spectroscopically identify H{alpha} emitters in both the cores of galaxy clusters as well as in field galaxies. We find a large cluster-to-cluster scatter in the star formation rates within a projected radius of 500kpc, and many of our clusters (~60%) have significant levels of star formation within a projected radius of 200kpc. A stacking analysis reveals that dust reddening in these star-forming galaxies is positively correlated with stellar mass and may be higher in the field than the cluster at a fixed stellar mass. This may indicate a lower amount of gas in star-forming cluster galaxies than in the field population. Also, H{alpha} equivalent widths of star-forming galaxies in the cluster environment are still suppressed below the level of the field. This suppression is most significant for lower mass galaxies (logM_*_<10.0M_{sun}_). We therefore conclude that environmental effects are still important at 1.0<z<1.5 for star-forming galaxies in galaxy clusters with logM_*_<~10.0M_{sun}_.
1133. HST observations of carbon in spiral galaxies
ID:
ivo://CDS.VizieR/J/ApJ/513/168
Title:
HST observations of carbon in spiral galaxies
Short Name:
J/ApJ/513/168
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present measurements of the gas-phase abundance ratio C/O in six H II regions in the spiral galaxies M101 and NGC 2403, based on ultraviolet spectroscopy using the Faint Object Spectrograph on the Hubble Space Telescope. The ratios of C to O increase systematically with O/H in both galaxies, from log(C/O){~=}-0.8 at log(O/H){~=}-4.0 to log(C/O){~=}-0.1 at log(O/H){~=}-3.4. C/N shows no correlation with O/H. The rate of increase of C/O is somewhat uncertain because of uncertainty as to the appropriate UV reddening law and uncertainty in the metallicity dependence on grain depletions. However, the trend of increasing C/O with O/H is clear, confirming and extending the trend in C/O indicated previously from observations of irregular galaxies. Our data indicate that the radial gradients in C/H across spiral galaxies are steeper than the gradients in O/H. Comparing the data to chemical-evolution models for spiral galaxies shows that models in which the massive star yields do not vary with metallicity predict radial C/O gradients that are much flatter than the observed gradients.
1134. HST observations of QSOs with medium spectra
ID:
ivo://CDS.VizieR/J/ApJ/818/113
Title:
HST observations of QSOs with medium spectra
Short Name:
J/ApJ/818/113
Date:
21 Oct 2021
Publisher:
CDS
Description:
We use the Hubble Space Telescope (HST) archive of ultraviolet (UV) quasar spectroscopy to conduct the first blind survey for damped Ly{alpha} absorbers (DLAs) at low redshift (z<1.6). Our statistical sample includes 463 quasars with spectral coverage spanning a total redshift path {Delta}z=123.3 or an absorption path {Delta}X=229.7. Within this survey path, we identify 4 DLAs defined as absorbers with HI column density N_HI_>=10^20.3^/cm2, which implies an incidence per absorption length lDLA(X)=0.017_-0.008_^+0.014^ at a median survey path redshift of z=0.623. While our estimate of l_DLA_(X) is lower than earlier estimates at z~0 from HI 21cm emission studies, the results are consistent within the measurement uncertainties. Our data set is too small to properly sample the N_HI_ frequency distribution function f(N_HI_,X), but the observed distribution agrees with previous estimates at z>2. Adopting the z>2 shape of f(N_HI_, X), we infer an HI mass density at z~0.6 of {rho}_HI_^DLA^=0.25_-0.12_^+0.20^. This is significantly lower than previous estimates from targeted DLA surveys with the HST, but consistent with results from low-z HI 21cm observations, and suggests that the neutral gas density of the universe has been decreasing over the past 10Gyr.
1135. HST phot. & GMOS spectra of Lynx E & W clusters
ID:
ivo://CDS.VizieR/J/ApJ/881/42
Title:
HST phot. & GMOS spectra of Lynx E & W clusters
Short Name:
J/ApJ/881/42
Date:
21 Oct 2021
Publisher:
CDS
Description:
Few detailed investigations of stellar populations in passive galaxies beyond z~1 are based on deep spectroscopic observations, due to the difficulty in obtaining such data. We present a study of stellar populations, structure, and mass-to-light ratios (M/L) of a large sample of bulge-dominated galaxies in the two z=1.27 clusters Lynx E and Lynx W, based on deep ground-based optical spectroscopy combined with imaging from the Hubble Space Telescope. We find that Lynx E has a well-defined core of red passive galaxies, while Lynx W lacks such a core. If all the sample galaxies evolve similarly in size from z=1.27 to the present, the data would allow only 0.1dex size growth at a fixed dynamical mass. However, to link the Lynx central galaxies to brightest cluster galaxies similar to those of low-redshift clusters, the Lynx galaxies would have to grow by at least a factor 5, possibly through major merging. The M/L ratios and the Balmer absorption lines of the Lynx galaxies are consistent with passive evolution of the stellar populations from z=1.27 to the present and support ages of 1-3Gyr. The galaxies in the outskirts of the clusters contain younger stellar populations than found in the cluster cores. However, when evolved passively to z~0 both populations are consistent with the observed populations in the Coma cluster galaxies. The bulge-dominated emission line galaxies in the clusters are dominated by stellar populations with subsolar metallicities. Thus, additional enrichment of these is required to produce Coma-like stellar populations by z~0.
1136. HST QSO Catalog
ID:
ivo://CDS.VizieR/J/ApJ/736/42
Title:
HST QSO Catalog
Short Name:
J/ApJ/736/42
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a survey for optically thick Lyman limit absorbers at z<2.6 using archival Hubble Space Telescope observations with the Faint Object Spectrograph and Space Telescope Imaging Spectrograph. We identify 206 Lyman limit systems (LLSs), increasing the number of cataloged LLSs at z<2.6 by a factor of ~10.
1137. HST spectral light curve of HAT-P-41
ID:
ivo://CDS.VizieR/J/AJ/161/51
Title:
HST spectral light curve of HAT-P-41
Short Name:
J/AJ/161/51
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a comprehensive analysis of the 0.3-5{mu}m transit spectrum for the inflated hot Jupiter HAT-P-41b. The planet was observed in transit with Hubble STIS and WFC3 as part of the Hubble Panchromatic Comparative Exoplanet Treasury (PanCET) program, and we combine those data with warm Spitzer transit observations. We extract transit depths from each of the data sets, presenting the STIS transit spectrum (0.29-0.93{mu}m) for the first time. We retrieve the transit spectrum both with a free-chemistry retrieval suite (AURA) and a complementary chemical equilibrium retrieval suite (PLATON) to constrain the atmospheric properties at the day-night terminator. Both methods provide an excellent fit to the observed spectrum. Both AURA and PLATON retrieve a metal-rich atmosphere for almost all model assumptions (most likely O/H ratio of log_10_Z/Z{odot}=1.46_-0.68_^+0.53^ and log_10_Z/Z{odot}=2.33_-0.25_^+0.23^, respectively); this is driven by a 4.9{sigma} detection of H_2_O as well as evidence of gas absorption in the optical (>2.7{sigma} detection) due to Na, AlO, and/or VO/TiO, though no individual species is strongly detected. Both retrievals determine the transit spectrum to be consistent with a clear atmosphere, with no evidence of haze or high-altitude clouds. Interior modeling constraints on the maximum atmospheric metallicity (log_10_Z/Z{odot}<1.7) favor the AURA results. The inferred elemental oxygen abundance suggests that HAT-P-41b has one of the most metal-rich atmospheres of any hot Jupiters known to date. Overall, the inferred high metallicity and high inflation make HAT-P-41b an interesting test case for planet formation theories.
1138. HST spectroscopic LCs of Kepler 51b & 51d
ID:
ivo://CDS.VizieR/J/AJ/159/57
Title:
HST spectroscopic LCs of Kepler 51b & 51d
Short Name:
J/AJ/159/57
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Kepler mission revealed a class of planets known as "super-puffs," with masses only a few times larger than Earth's but radii larger than Neptune, giving them very low mean densities. All three of the known planets orbiting the young solar-type star Kepler 51 are super-puffs. The Kepler 51 system thereby provides an opportunity for a comparative study of the structures and atmospheres of this mysterious class of planets, which may provide clues about their formation and evolution. We observed two transits each of Kepler 51b and 51d with the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope. Combining new WFC3 transit times with reanalyzed Kepler data and updated stellar parameters, we confirmed that all three planets have densities lower than 0.1g/cm^3^. We measured the WFC3 transmission spectra to be featureless between 1.15 and 1.63{mu}m, ruling out any variations greater than 0.6 scale heights (assuming a H/He-dominated atmosphere), thus showing no significant water absorption features. We interpreted the flat spectra as the result of a high-altitude aerosol layer (pressure <3mbar) on each planet. Adding this new result to the collection of flat spectra that have been observed for other sub-Neptune planets, we find support for one of the two hypotheses introduced by Crossfield & Kreidberg (2017AJ....154..261C), that planets with cooler equilibrium temperatures have more high-altitude aerosols. We strongly disfavor their other hypothesis that the H/He mass fraction drives the appearance of large-amplitude transmission features.
1139. HST/STIS FUV spectra of K2-18
ID:
ivo://CDS.VizieR/J/A+A/634/L4
Title:
HST/STIS FUV spectra of K2-18
Short Name:
J/A+A/634/L4
Date:
21 Oct 2021
Publisher:
CDS
Description:
K2-18 b is a transiting mini-Neptune that orbits a nearby (38pc), cool M3 dwarf and is located inside its region of temperate irradiation. We report on the search for hydrogen escape from the atmosphere K2-18 b using Lyman-{alpha} transit spectroscopy with the Space Telescope Imaging Spectrograph (STIS) instrument installed on the Hubble Space Telescope (HST). We analyzed the time-series of fluxes of the stellar Lyman-{alpha} emission of K2-18 in both its blue- and redshifted wings. We found that the average blueshifted emission of K2-18 decreases by 67%+/-18% during the transit of the planet compared to the pre-transit emission, tentatively indicating the presence of H atoms escaping vigorously and being blown away by radiation pressure. This interpretation is not definitive because it relies on one partial transit. Based on the reconstructed Lyman-{alpha} emission of K2-18, we estimate an EUV irradiation in the range 10^1^-10^2^erg/s/cm^2^ and a total escape rate on the order of 10^8^g/s. The inferred escape rate suggests that the planet will lose only a small fraction (<1%) of its mass and retain its volatile-rich atmosphere during its lifetime. More observations are needed to rule out stellar variability effects, confirm the in-transit absorption, and better assess the atmospheric escape and high-energy environment of K2-18 b.
1140. HST/STIS near-UV spectrum of {eta} Telescopii
ID:
ivo://CDS.VizieR/J/AJ/162/235
Title:
HST/STIS near-UV spectrum of {eta} Telescopii
Short Name:
J/AJ/162/235
Date:
14 Mar 2022 07:38:34
Publisher:
CDS
Description:
We present far- and near-ultraviolet absorption spectroscopy of the ~23Myr edge-on debris disk surrounding the A0V star {eta}Telescopii, obtained with the Hubble Space Telescope Space Telescope Imaging Spectrograph. We detect absorption lines from CI, CII, OI, MgII, AlII, SiII, SII, MnII, FeII, and marginally NI. The lines show two clear absorption components at -22.7{+/-}0.5km/s and -17.8{+/-}0.7km/s, which we attribute to circumstellar (CS) and interstellar gas, respectively. CO absorption is not detected, and we find no evidence for star-grazing exocomets. The CS absorption components are blueshifted by -16.9{+/-}2.6km/s in the star's reference frame, indicating that they are outflowing in a radiatively driven disk wind. We find that the C/Fe ratio in the {eta}Tel CS gas is significantly higher than the solar ratio, as is the case in the {beta}Pic and 49Cet debris disks. Unlike those disks, however, the measured C/O ratio in the {eta}Tel CS gas is consistent with the solar value. Our analysis shows that because {eta}Tel is an earlier type star than {beta}Pic and 49Cet, with more substantial radiation pressure at the dominant CII transitions, this species cannot bind the CS gas disk to the star as it does for {beta}Pic and 49Cet, resulting in the disk wind.

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