- ID:
- ivo://CDS.VizieR/J/AJ/132/2135
- Title:
- High-resolution spectroscopy in Tr 37
- Short Name:
- J/AJ/132/2135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the Hectochelle multifiber spectrograph, we have obtained high-resolution (R~34000) spectra in the H{alpha} region for a large number of stars in the 4Myr old cluster Tr 37, containing 146 previously known members and 26 newly identified ones. We present the H{alpha} line profiles of all members, compare them to our IR observations of dusty disks (Two Micron All Sky Survey JHK + IRAC + MIPS 24um), use the radial velocities as a membership criterion, and calculate the rotational velocities.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/478/3740
- Title:
- High-z LAEs and LBGs in SHARDS survey
- Short Name:
- J/MNRAS/478/3740
- Date:
- 11 Mar 2022 14:56:32
- Publisher:
- CDS
- Description:
- We have undertaken a comprehensive search for both Lyman alpha emitters (LAEs) and Lyman break galaxies (LBGs) in the Survey for High-z Absorption Red and Dead Sources (SHARDS) Survey of the Great Observatories Origins Deep Survey North field. SHARDS is a deep imaging survey, made with the 10.4m Gran Telescopio Canarias, employing 25 medium band filters in the range from 500 to 941nm. This is the first time that both LAEs and LBGs are surveyed simultaneously in a systematic way in a large field. We draw a sample of 1558 sources; 528 of them are LAEs. Most of the sources (1434) show rest-frame UV continua. A minority of them (124) are pure LAEs with virtually no continuum detected in SHARDS. We study these sources from z~3.35 up to z~6.8, well into the epoch of reionization. Note that surveys done with just one or two narrow band filters lack the possibility to spot the rest-frame UV continuum present in most of our LAEs. We derive redshifts, star formation rates, Ly{alpha} equivalent widths, and luminosity functions (LFs). Grouping within our sample is also studied, finding 92 pairs or small groups of galaxies at the same redshift separated by less than 60 comoving kpc. In addition, we relate 87 and 55 UV-selected objects with two known overdensities at z=4.05 and z=5.198, respectively. Finally, we show that surveys made with broad-band filters are prone to introduce many unwanted sources (~20 per cent interlopers), which means that previous studies may be overestimating the calculated LFs, specially at the faint end.
- ID:
- ivo://CDS.VizieR/J/ApJ/764/9
- Title:
- High-z MgII absorption QSOs with FIRE. II.
- Short Name:
- J/ApJ/764/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed study of HI and metals for 110 MgII absorption systems discovered at 1.98<=z<=5.33 in the infrared spectra of high-redshift QSOs. Using new measurements of rest-frame UV lines from optical spectra of the same targets, we compare the high-redshift sample with carefully constructed low-redshift control samples from the literature to study evolutionary trends from z=0-->5.33 (>12Gyr). We observe a significant strengthening in the characteristic N(HI) for fixed MgII equivalent width as one moves toward higher redshift. Indeed, at our sample's mean <Z>=3.402, all MgII systems are either damped Ly{alpha} absorbers (DLAs) or sub-DLAs, with 40.7% of systems exceeding the DLA threshold (compared to 16.7% at <Z>=0.927). We set lower limits on the metallicity of the MgII systems where we can measure HI; these results are consistent with the full DLA population. The classical MgII systems (W({lambda}2796)_0_=0.3-1.0{AA}), which preferentially associate with sub-DLAs, are quite metal rich at ~0.1 solar. We applied quantitative classification metrics to our absorbers to compare with low-redshift populations, finding that weak systems are similar to classic MgII absorbers at low redshift. The strong systems either have very large MgII and FeII velocity spreads implying non-virialized dynamics or are more quiescent DLAs. There is tentative evidence that the kinetically complex systems evolve in similar fashion to the global star formation rate. We speculate that if weaker MgII systems represent accreting gas as suggested by recent studies of galaxy-absorber inclinations, then their high metal abundance suggests re-accretion of recently ejected material rather than first-time infall from the metal-poor intergalactic medium, even at early times.
- ID:
- ivo://CDS.VizieR/J/AN/341/908
- Title:
- 308 Hipparcos stars EW Li and spectra
- Short Name:
- J/AN/341/908
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Since early 2015 a spectroscopic monitoring campaign of selected Hipparcos stars is going on at the University Observatory Jena. The aim of this project is to search for lithium at 6708{AA}, which is a youth indicator, and to measure its equivalent width to identify young runaway stars in the sample (age<=50Myr) along with the Gaia data.
- ID:
- ivo://CDS.VizieR/J/ApJ/770/107
- Title:
- Host galaxies of SNIa from SNfactory
- Short Name:
- J/ApJ/770/107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometric and spectroscopic observations of galaxies hosting Type Ia supernovae (SNe Ia) observed by the Nearby Supernova Factory. Combining Galaxy Evolution Explorer (GALEX) UV data with optical and near-infrared photometry, we employ stellar population synthesis techniques to measure SN Ia host galaxy stellar masses, star formation rates (SFRs), and reddening due to dust. We reinforce the key role of GALEX UV data in deriving accurate estimates of galaxy SFRs and dust extinction. Optical spectra of SN Ia host galaxies are fitted simultaneously for their stellar continua and emission lines fluxes, from which we derive high-precision redshifts, gas-phase metallicities, and H{alpha}-based SFRs. With these data we show that SN Ia host galaxies present tight agreement with the fiducial galaxy mass-metallicity relation from Sloan Digital Sky Survey (SDSS) for stellar masses log(M_*_/M_{sun}_)>8.5 where the relation is well defined. The star formation activity of SN Ia host galaxies is consistent with a sample of comparable SDSS field galaxies, though this comparison is limited by systematic uncertainties in SFR measurements. Our analysis indicates that SN Ia host galaxies are, on average, typical representatives of normal field galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/788/39
- Title:
- Hot Jupiter exoplanets host stars EW and abundances
- Short Name:
- J/ApJ/788/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The relative abundances of carbon and oxygen have long been recognized as fundamental diagnostics of stellar chemical evolution. Now, the growing number of exoplanet observations enable estimation of these elements in exoplanetary atmospheres. In hot Jupiters, the C/O ratio affects the partitioning of carbon in the major observable molecules, making these elements diagnostic of temperature structure and composition. Here we present measurements of carbon and oxygen abundances in 16 stars that host transiting hot Jupiter exoplanets, and we compare our C/O ratios to those measured in larger samples of host stars, as well as those estimated for the corresponding exoplanet atmospheres. With standard stellar abundance analysis we derive stellar parameters as well as [C/H] and [O/H] from multiple abundance indicators, including synthesis fitting of the [O I] {lambda}6300 line and non-LTE corrections for the O I triplet. Our results, in agreement with recent suggestions, indicate that previously measured exoplanet host star C/O ratios may have been overestimated. The mean transiting exoplanet host star C/O ratio from this sample is 0.54 (C/O_{sun}_=0.54), versus previously measured C/O_host star_ means of ~0.65-0.75. We also observe the increase in C/O with [Fe/H] expected for all stars based on Galactic chemical evolution; a linear fit to our results falls slightly below that of other exoplanet host star studies but has a similar slope. Though the C/O ratios of even the most-observed exoplanets are still uncertain, the more precise abundance analysis possible right now for their host stars can help constrain these planets' formation environments and current compositions.
- ID:
- ivo://CDS.VizieR/J/A+A/546/A105
- Title:
- HR8752 evolving through the void
- Short Name:
- J/A+A/546/A105
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The main paper on the hypergiant HR8752 evolving through the void combines observational data from various sources: new spectral data, new and already published (B-V), V data. it also describes a new three-dimensional chebychev interpolating code, and gives information on the temperature calibration for hypergiants, and adds some extra Tables on colour excess and historical context (cf. below). The electronic appendix contains a number of tables, too large for publishing in the paper. In the text and in the appendix, they are referred to as Table Axx, resp. Cxx. We note, however, that tables A1.1 to A1.6 in Section 2 of the main paper are here referred to as tables appena11 to appena16. The observational tables appena11 to appena16, appena2, appena3, appena4 all refer to Section 2 in the main paper, while tables appena5, appena6, appena7, appena8 are used in Section 3 of the main paper. The technical table appenc1 describes the three-dimensional chebychev interpolation method used in Section 2 of the main paper. The second technical table appenc2 describes the (hypergiant) temperature calibration and transformation codes between Mk, Teff, and (B-V) data, used in Section 3 of the main paper. Table appena9 discusses some measured colour excesses (Section 3.3 of the main paper). Table appena10 discusses the possibility of historical context (Section 5.11 of the main paper).
- ID:
- ivo://CDS.VizieR/J/ApJS/140/143
- Title:
- HST FOS spectral atlas
- Short Name:
- J/ApJS/140/143
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyzed the absorption line spectra of all quasars observed with the high-resolution gratings of the Faint Object Spectrograph on board the Hubble Space Telescope. We examined 788 spectra for 334 quasars and present line lists and identifications of absorption lines in the spectra of 271 of them. Analysis of the statistics of the Ly{alpha} and metal absorption systems are presented in companion papers. The data and several analysis products are available on the authors' Web site, http://lithops.as.arizona.edu/~jill/QuasarSpectra .
- 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}_.
- ID:
- ivo://CDS.VizieR/J/AJ/130/2043
- Title:
- HST paired and isolated galaxies
- Short Name:
- J/AJ/130/2043
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compare the structural properties of two classes of galaxies at intermediate redshift: those in dynamically close galaxy pairs, and those that are isolated. Both samples are selected from the Canadian Network for Observational Cosmology field galaxy redshift survey (CNOC2, Cat. <J/ApJS/129/475>) and have redshifts in the range 0.1<z<0.6. Hubble Space Telescope WFPC2 images were acquired as part of a snapshot survey and were used to measure bulge fraction and asymmetry for these galaxies.
