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1151. HST/STIS spectra of alpha Cen A
ID:
ivo://CDS.VizieR/J/A+A/415/331
Title:
HST/STIS spectra of alpha Cen A
Short Name:
J/A+A/415/331
Date:
21 Oct 2021
Publisher:
CDS
Description:
This table is part of a paper is which a study of the alpha Cen A spectrum recorded with the E140 grating by HST/STIS between 1140 and 1670{AA} is presented. In this spectrum the authors have identified a total of 662 emission features of which 77 are due to blends of two or more lines, 71 are due to unidentified transitions, and 514 are identified as due to single emission lines.
1152. HST strong lensing analysis of PLCKG287.0+32.9
ID:
ivo://CDS.VizieR/J/ApJ/839/L11
Title:
HST strong lensing analysis of PLCKG287.0+32.9
Short Name:
J/ApJ/839/L11
Date:
21 Oct 2021
Publisher:
CDS
Description:
Since galaxy clusters sit at the high end of the mass function, the number of galaxy clusters both massive and concentrated enough to yield particularly large Einstein radii poses useful constraints on cosmological and structure formation models. To date, less than a handful of clusters are known to have Einstein radii exceeding ~40" (for a source at z_s_~2, nominally). Here, we report an addition to that list of the Sunyaev-Zel'dovich (SZ) selected cluster, PLCKG287.0+32.9 (z=0.38), the second-highest SZ-mass (M500) cluster from the Planck catalog. We present the first strong-lensing analysis of the cluster, identifying 20 sets of multiply imaged galaxies and candidates in new Hubble Space Telescope (HST) data, including a long, l~22" giant arc, as well as a quadruply imaged, apparently bright (magnified to J_F110W_=25.3 AB), likely high-redshift dropout galaxy at z_phot_=6.90 [6.13-8.43] (95% C.I.). Our analysis reveals a very large critical area (1.55arcmin^2^, z_s_~2), corresponding to an effective Einstein radius of {theta}_E_~42". The model suggests the critical area will expand to 2.58arcmin^2^ ({theta}_E_~54") for sources at z_s_~10. Our work adds to recent efforts to model very massive clusters toward the launch of the James Webb Space Telescope, in order to identify the most useful cosmic lenses for studying the early universe. Spectroscopic redshifts for the multiply imaged galaxies and additional HST data will be necessary for refining the lens model and verifying the nature of the z~7 dropout.
1153. HST survey for Lyman limit systems. I.
ID:
ivo://CDS.VizieR/J/ApJS/195/16
Title:
HST survey for Lyman limit systems. I.
Short Name:
J/ApJS/195/16
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a set of 71 quasars observed in the near ultraviolet with the PR200L prism on the Advanced Camera for Surveys and the G280 grism on the Wide Field Camera 3 (WFC3) on board the Hubble Space Telescope. The quasars were selected from the Sloan Digital Sky Survey data to search for intervening Lyman limit system (LLS) absorption. The sample was subjected to the constraints that the quasars have AB magnitude g'<18.5, quasar emission redshift 2.3<z_em_<2.6, and lack strong BAL or z~z_em_ absorption. The median emission redshift of the sample is {bar}z=2.403. The data were all processed using custom data reduction pipelines, and the one-dimensional spectra have sufficient signal-to-noise ratio and resolution to easily identify absorption from LLS over the redshift range 1.2<z<2.5. The WFC3 data presented here are the first non-calibration spectra from the G280 grism.
1154. HST survey for Lyman limit systems. II.
ID:
ivo://CDS.VizieR/J/ApJ/765/137
Title:
HST survey for Lyman limit systems. II.
Short Name:
J/ApJ/765/137
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the first science results from our Hubble Space Telescope survey for Lyman limit absorption systems (LLS) using the low dispersion spectroscopic modes of the Advanced Camera for Surveys and the Wide Field Camera 3. Through an analysis of 71 quasars, we determine the incidence frequency of LLS per unit redshift and per unit path length, l(z) and l(X), respectively, over the redshift range 1<z<2.6, and find a weighted mean of l(X)=0.29+/-0.05 for 2.0<z<2.5 through a joint analysis of our sample and that of Ribaudo et al. (2011, J/ApJ/736/42). Through stacked spectrum analysis, we determine a median (mean) value of the mean free path to ionizing radiation at z=2.4 of {lambda}^912^_mfp_=243(252)h^-1^_72_Mpc, with an error on the mean value of +/-43h^-1^_72_Mpc. We also re-evaluate the estimates of {lambda}^912^_mfp_ from Prochaska et al. (2010, J/ApJ/718/392) and place constraints on the evolution of {lambda}^912^_mfp_ with redshift, including an estimate of the "breakthrough" redshift of z=1.6. Consistent with results at higher z, we find that a significant fraction of the opacity for absorption of ionizing photons comes from systems with N_HI_<=10^17.5^cm^-2^ with a value for the total Lyman opacity of {tau}^Lyman^_eff_=0.40+/-0.15. Finally, we determine that at minimum, a 5-parameter (4 power law) model is needed to describe the column density distribution function f(N_HI_,X) at z~2.4, find that f(N_HI_,X) undergoes no significant change in shape between z~2.4 and z~3.7, and provide our best fit model for f(N_HI_,X).
1155. HST WFC3 ERS : emission-line galaxies
ID:
ivo://CDS.VizieR/J/AJ/141/14
Title:
HST WFC3 ERS : emission-line galaxies
Short Name:
J/AJ/141/14
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present grism spectra of emission-line galaxies (ELGs) from 0.6 to 1.6um from the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope. These new infrared grism data augment previous optical Advanced Camera for Surveys G800L 0.6-0.95um grism data in GOODS-South from the PEARS program, extending the wavelength coverage well past the G800L red cutoff. The Early Release Science (ERS) grism field was observed at a depth of two orbits per grism, yielding spectra of hundreds of faint objects, a subset of which is presented here. ELGs are studied via the H{alpha}, [OIII], and [OII] emission lines detected in the redshift ranges 0.2~<z~<1.4, 1.2~<z~<2.2, and 2.0~<z~<3.3, respectively, in the G102 (0.8-1.1um; R~=210) and G141 (1.1-1.6um; R~=130) grisms.
1156. Hubble Legacy Archive ACS grism data
ID:
ivo://CDS.VizieR/J/A+A/530/A86
Title:
Hubble Legacy Archive ACS grism data
Short Name:
J/A+A/530/A86
Date:
21 Oct 2021
Publisher:
CDS
Description:
A public release of slitless spectra, obtained with ACS/WFC and the G800L grism, is presented. Spectra were automatically extracted in a uniform way from 153 archival fields (or "associations") distributed across the two Galactic caps, covering all observations to 2008. The ACS G800L grism provides a wavelength range of 0.55-1.00um, with a dispersion of 40{AA}/pixel and a resolution of ~80{AA} for point-like sources. The ACS G800L images and matched direct images were reduced with an automatic pipeline that handles all steps from archive retrieval, alignment and astrometric calibration, direct image combination, catalogue generation, spectral extraction and collection of metadata. The large number of extracted spectra (73,581) demanded automatic methods for quality control and an automated classification algorithm was trained on the visual inspection of several thousand spectra. The final sample of quality controlled spectra includes 47919 datasets (65% of the total number of extracted spectra) for 32149 unique objects, with a median i_AB_-band magnitude of 23.7, reaching 26.5 AB for the faintest objects. Each released dataset contains science-ready 1D and 2D spectra, as well as multi-band image cutouts of corresponding sources and a useful preview page summarising the direct and slitless data, astrometric and photometric parameters. This release is part of the continuing effort to enhance the content of the Hubble Legacy Archive (HLA) with highly processed data products which significantly facilitate the scientific exploitation of the Hubble data. In order to characterize the slitless spectra, emission-line flux and equivalent width sensitivity of the ACS data were compared with public ground-based spectra in the GOODS-South field. An example list of emission line galaxies with two or more identified lines is also included, covering the redshift range 0.2-4.6. Almost all redshift determinations outside of the GOODS fields are new. The scope of science projects possible with the ACS slitless release data is large, from studies of Galactic stars to searches for high redshift galaxies.
1157. Hubble spectroscopy of LB-1 (LS V +22 25)
ID:
ivo://CDS.VizieR/J/A+A/649/A167
Title:
Hubble spectroscopy of LB-1 (LS V +22 25)
Short Name:
J/A+A/649/A167
Date:
22 Feb 2022
Publisher:
CDS
Description:
LB-1 has variously been proposed as either an X-ray dim B-type star plus black hole (B+BH) binary, or a Be star plus an inflated stripped star (Be+Bstr) binary. The Space Telescope Imaging Spectrograph (STIS) on board HST was used to obtain a flux-calibrated spectrum that is compared with non-LTE spectral energy distributions (SED) and line profiles for the proposed models. The Hubble data, together with the Gaia EDR3 parallax, provide tight constraints on the properties and stellar luminosities of the system. In the case of the Be+Bstr model we adopt the published flux ratio for the Be and Bstr stars, re-determine the Teff of the Bstr using the silicon ionization balance, and infer Teff for the Be star from the fit to the SED. We derive stellar parameters consistent with previous results, but with greater precision enabled by the Hubble SED. While the Be+Bstr model is a better fit to the HeI lines and cores of the Balmer lines in the optical, the B+BH model provides a better fit to the SiIV resonance lines in the UV. The analysis also implies that the Bstr star has roughly twice solar silicon abundance, which is difficult to reconcile with a stripped star origin. The Be star on the other hand has a rather low luminosity, and a spectroscopic mass inconsistent with its possible dynamical mass. The fit to the UV can be significantly improved by reducing the Teff and radius of the Be star, though at the expense of leading to a different mass ratio. In the B+BH model, the single B-type spectrum is a good match to the UV spectrum. Adopting a mass ratio of 5.1+/-0.1 (Liu et al., 2020ApJ...900...42L) implies a BH mass of 21^+9^_-8_ solar masses.
1158. Hydra/Antlia extension redshifts
ID:
ivo://CDS.VizieR/J/A+A/297/617
Title:
Hydra/Antlia extension redshifts
Short Name:
J/A+A/297/617
Date:
21 Oct 2021
Publisher:
CDS
Description:
Spectroscopic observations have been carried out for galaxies in the Milky Way with the 1.9m telescope of the South African Astronomical Observatory (SAAO). The galaxies were selected from a deep optical galaxy search covering 266deg<~l<~296deg, |b|<~10deg (Kraan-Korteweg 1994). This is in the extension of the Hydra and Antlia clusters and in the approximate direction of the dipole anisotropy in the Cosmic Microwave Background radiation.
1159. Hydrogen in diffuse molecular clouds
ID:
ivo://CDS.VizieR/J/A+A/600/A2
Title:
Hydrogen in diffuse molecular clouds
Short Name:
J/A+A/600/A2
Date:
21 Oct 2021
Publisher:
CDS
Description:
Recent sub-millimeter and far-infrared wavelength observations of absorption in the rotational ground state lines of various simple molecules against distant Galactic continuum sources have opened the possibility to study the chemistry of diffuse molecular clouds Milky Way-wide. In order to calculate abundances the column densities of molecular and atomic hydrogen, HI, must be known. We aim at determining the atomic hydrogen column densities for diffuse clouds located on the sight lines toward a sample of prominent high mass star forming regions that were intensely studied with the HIFI instrument onboard Herschel. Based on Jansky Very Large Array data, we employ the 21-cm HI absorption-line technique to construct profiles of the HI opacity versus radial velocity toward our target sources. These profiles are combined with lower resolution archival data of extended HI emission to calculate the HI column densities of the individual clouds along the sight lines. We employ Bayesian inference to estimate the uncertainties of the derived quantities. Our study delivers reliable estimates of the atomic hydrogen column density for a large number of diffuse molecular clouds at various Galactocentric distances. Together with column densities of molecular hydrogen derived from its surrogates observed with HIFI, the measurements can be used to characterize the clouds and, e.g., investigate the dependence of their chemistry on the molecular fraction.
1160. Hydrogen Lyman and Balmer line profiles
ID:
ivo://CDS.VizieR/J/MNRAS/448/2332
Title:
Hydrogen Lyman and Balmer line profiles
Short Name:
J/MNRAS/448/2332
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new calculations of unified line profiles for hydrogen perturbed by collisions with protons. We report on new calculations of the potential energies and dipole moments which allow the evaluation of profiles for the lines of the Lyman series up to Lyman {delta} and the Balmer series up to Balmer 10. Unified calculations only existed for the lines Lyman {alpha} to Lyman {gamma} and Balmer {alpha} including the H_2_^+^ quasi-molecule. These data are available as online material accompanying this paper and should be included in atmosphere models, in place of the Stark effect of protons, since the quasi-molecular contributions cause not only satellites, but large asymmetries that are unaccounted for in models that assume that Stark broadening of electrons and that of protons are equal.

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