- ID:
- ivo://CDS.VizieR/J/AJ/160/37
- Title:
- Intergalac. medium opacity from Lyman-break galaxies
- Short Name:
- J/AJ/160/37
- Date:
- 08 Dec 2021
- Publisher:
- CDS
- Description:
- We measure the effective opacity ({tau}_eff_) of the intergalactic medium from the composite spectra of 281 Lyman-break galaxies in the redshift range 2<~z<~3. Our spectra are taken from the COSMOS Ly{alpha} Mapping And Tomographic Observations survey derived from the Low Resolution Imaging Spectrometer on the W.M. Keck I telescope. We generate composite spectra in two redshift intervals and fit them with spectral energy distribution (SED) models composed of simple stellar populations. Extrapolating these SED models into the Ly{alpha} forest, we measure the effective Ly{alpha} opacity ({tau}_eff_) in the 2.02<~z<~2.44 range. At z=2.22, we estimate {tau}_eff_=0.159{+/-}0.001 from a power-law fit to the data. These measurements are consistent with estimates from quasar analyses at z<2.5 indicating that the systematic errors associated with normalizing quasar continua are not substantial. We provide a Gaussian processes model of our results and previous {tau}_eff_ measurements that describes the steep redshift evolution in {tau}_eff_ from z=1.5-4.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/683/L115
- Title:
- Intermediate-line region in quasars
- Short Name:
- J/ApJ/683/L115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on a systematic investigation of the H{beta} and FeII emission lines in a sample of 568 quasars within z<0.8 selected from the Sloan Digital Sky Survey quasar catalog (DR5, Cat. VII/252). The conventional broad H{beta} emission line can be decomposed into two components: one with intermediate velocity width and another with very broad width. The velocity shift and equivalent width of the intermediate-width component do not correlate with those of the very broad component of H{beta}, but its velocity shift and width do resemble FeII. Moreover, the width of the very broad component is roughly 2.5 times that of the intermediate-width component. These characteristics strongly suggest the existence of an intermediate-line region, whose kinematics seem to be dominated by infall, located at the outer portion of the broad-line region.
- ID:
- ivo://CDS.VizieR/J/A+A/622/A72
- Title:
- Intermediate-mass T Tau stars spectra
- Short Name:
- J/A+A/622/A72
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The origin of the fossil magnetic fields detected in 5 to 10% of intermediate-mass main sequence stars is still highly debated. We want to bring observational constraints to a large population of intermediate-mass pre-main sequence (PMS) stars in order to test the theory that convective-dynamo fields generated during the PMS phases of stellar evolution can occasionally relax into fossil fields on the main sequence. Using distance estimations, photometric measurements, and spectropolarimetric data from HARPSpol and ESPaDOnS of 38 intermediate-mass PMS stars, we determined fundamental stellar parameters (T_eff_, L and vsini) and measured surface magnetic field characteristics (including detection limits for non-detections, and longitudinal fields and basic topologies for positive detections). Using PMS evolutionary models, we determined the mass, radius, and internal structure of these stars. We compared different PMS models to check that our determinations were not model- dependant. We then compared the magnetic characteristics of our sample accounting for their stellar parameters and internal structures. Results: We detect magnetic fields in about half of our sample. About 90% of the magnetic stars have outer convective envelopes larger than ~25% of the stellar radii, and heavier than ~2% of the stellar mass. Going to higher mass, we find that the magnetic incidence in intermediate-mass stars drops very quickly, within a time-scale of the order of few times 0.1Myr. Finally, we propose that intermediate-mass T Tauri stars with large convective envelopes, close to the fully convective limit, have complex fields and that their dipole component strengths may decrease as the sizes of their convective envelopes decrease, similar to lower-mass T Tauri stars.
- ID:
- ivo://CDS.VizieR/J/ApJS/147/61
- Title:
- Interstellar Ca I absorption
- Short Name:
- J/ApJS/147/61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-resolution (FWHM~0.3-1.5km/s) spectra, obtained with the AAT UHRF, the McDonald Observatory 2.7m coude spectrograph, and/or the KPNO coude feed, of interstellar Ca I absorption toward 30 Galactic stars. Comparisons of the column densities of Ca I, Ca II, K I, and other species - for individual components identified in the line profiles and also when integrated over entire lines of sight - yield information on relative electron densities and depletions (dependent on assumptions regarding the ionization equilibrium).
- ID:
- ivo://CDS.VizieR/III/148A
- Title:
- Interstellar lines catalogue
- Short Name:
- III/148A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A bibliographical catalogue of the interstellar lines has been prepared (2003 stars in our Galaxy, 86 stars in the Magellanic Clouds and 41 extragalactic objects), and 371 bibliographical references.
- ID:
- ivo://CDS.VizieR/J/MNRAS/367/1478
- Title:
- Interstellar NaI, TiII & CaIIK obs.
- Short Name:
- J/MNRAS/367/1478
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of interstellar NaI ({lambda}_air_=3302.37 and 3302.98{AA}), TiII ({lambda}_air_=3383.76{AA}) and CaIIK ({lambda}_air_=3933.66{AA}) absorption features for 74 sightlines towards O- and B-type stars in the Galactic disc. The data were obtained from the Ultraviolet and Visual Echelle Spectrograph Paranal Observatory Project (UVES POP), at a spectral resolution of 3.75km/s and with mean signal-to-noise ratios per pixel of 260, 300 and 430 for the NaI, TiII and CaII observations, respectively. Interstellar features were detected in all but one of the TiII sightlines and all of the CaII sightlines. The dependence of the column density of these three species with distance, height relative to the Galactic plane, HI column density, reddening and depletion relative to the solar abundance has been investigated. We also examine the accuracy of using the NaI column density as an indicator of that for HI. In general, we find similar strong correlations for both Ti and Ca, and weaker correlations for Na. Our results confirm the general belief that Ti and Ca occur in the same regions of the interstellar medium (ISM) and also that the TiII/CaII ratio is constant over all parameters. We hence conclude that the absorption properties of Ti and Ca are essentially constant under the general ISM conditions of the Galactic disc.
1177. Interstellar SiO sources
- ID:
- ivo://CDS.VizieR/J/A+AS/132/211
- Title:
- Interstellar SiO sources
- Short Name:
- J/A+AS/132/211
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of a survey of SiO emission using the 15-m SEST and the 20-m Onsala telescope are presented in two tables. The sample contains altogether 369 objects including 270 H2O masers, 19 OH masers and 62 IRAS sources with colours typical for ultracompact HII regions. The remaining target sources consist of dust continuum peaks a CS emission peak near H2O masers (12) and Herbig-Haro objects (6). The entries are arranged according to increasing right ascension.
- ID:
- ivo://CDS.VizieR/J/A+A/627/A124
- Title:
- INT near-Earth asteroids spectroscopic survey
- Short Name:
- J/A+A/627/A124
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The population of near-Earth asteroids (NEAs) shows a large variety of objects in terms of physical and dynamical properties. They are subject to planetary encounters and to strong solar wind and radiation effects. Their study is also motivated by practical reasons regarding space exploration and long-term probability of impact with the Earth. We aim to spectrally characterize a significant sample of NEAs with sizes in the range of ~0.25-5.5km (categorized as large), and search for connections between their spectral types and the orbital parameters. Optical spectra of NEAs were obtained using the Isaac Newton Telescope (INT) equipped with the IDS spectrograph. These observations are analyzed using taxonomic classification and by comparison with laboratory spectra of meteorites. A total number of 76 NEAs were observed. We spectrally classified 44 of them as Q/S-complex, 16 as B/C-complex, eight as V-types, and another eight belong to the remaining taxonomic classes. Our sample contains 27 asteroids categorized as potentially hazardous and 31 possible targets for space missions including (459872) 2014 EK24, (436724) 2011 UW158, and (67367) 2000 LY27. The spectral data corresponding to (276049) 2002 CE26 and (385186) 1994 AW1 shows the 0.7um feature which indicates the presence of hydrated minerals on their surface. We report that Q-types have the lowest perihelia (a median value and absolute deviation of 0.797+/-0.244AU) and are systematically larger than the S-type asteroids observed in our sample. We explain these observational evidences by thermal fatigue fragmentation as the main process for the rejuvenation of NEA surfaces. In general terms, the taxonomic distribution of our sample is similar to the previous studies and matches the broad groups of the inner main belt asteroids. Nevertheless, we found a wide diversity of spectra compared to the standard taxonomic types.
- ID:
- ivo://CDS.VizieR/J/A+A/376/28
- Title:
- Inversion of the HE 1122-1648 UVES spectrum
- Short Name:
- J/A+A/376/28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- File tablea1.dat contains the list of the Lyman-{alpha} absorption lines identified in the spectrum of HE 1122-1648 obtained during Science Verification of UVES at the VLT. We used the standard method of Voigt Profile fitting with VPFIT and with the inversion method described in the related paper. (Note that the printed version of the paper indicates HE 1122-1628, instead of the quasar HE 1122-1648).
- ID:
- ivo://CDS.VizieR/J/ApJ/842/121
- Title:
- Investigating Tully-Fisher relation with KMOS^3D^
- Short Name:
- J/ApJ/842/121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the stellar mass and baryonic mass Tully-Fisher relations (TFRs) of massive star-forming disk galaxies at redshift z~2.3 and z~0.9 as part of the KMOS^3D^ integral field spectroscopy survey. Our spatially resolved data allow reliable modeling of individual galaxies, including the effect of pressure support on the inferred gravitational potential. At fixed circular velocity, we find higher baryonic masses and similar stellar masses at z~2.3 as compared to z~0.9. Together with the decreasing gas-to-stellar mass ratios with decreasing redshift, this implies that the contribution of dark matter to the dynamical mass on the galaxy scale increases toward lower redshift. A comparison to local relations reveals a negative evolution of the stellar and baryonic TFR zero points from z=0 to z~0.9, no evolution of the stellar TFR zero point from z~0.9 to z~2.3, and a positive evolution of the baryonic TFR zero point from z~0.9 to z~2.3. We discuss a toy model of disk galaxy evolution to explain the observed nonmonotonic TFR evolution, taking into account the empirically motivated redshift dependencies of galactic gas fractions and the relative amount of baryons to dark matter on galaxy and halo scales.
