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1661. mm-dm-sized meteoroids spectral & orbital survey
ID:
ivo://CDS.VizieR/J/A+A/629/A71
Title:
mm-dm-sized meteoroids spectral & orbital survey
Short Name:
J/A+A/629/A71
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate the spectra, material properties and orbital distribution of mid-sized meteoroids. Our study aims to distinguish characteristics of different size populations of meteoroids and reveal the heterogeneity of identified meteoroid streams. The emission spectra and multi-station meteor trajectories were collected within the AMOS network observations. The sample is based on 202 meteors of -1 to -14 magnitude, corresponding to meteoroids of mm-dm in size. Overall increase of Na content compared to the population of mm-sized meteoroids was detected, reflecting weaker effects of space weathering processes on larger meteoroids. We report on very low ratio of pure iron meteoroids and the discovery of a new spectral group of Fe-rich meteors. The majority of meteoroids on asteroidal orbits were found to be chondritic. Thermal processes causing Na depletion and physical processes resulting in Na-rich spectra are described and linked to characteristically increased material strengths. Numerous major and minor shower meteors were identified in our sample, revealing various degrees of heterogeneity within Halley-type, ecliptical and sungrazing meteoroid streams.
1662. 3mm molecular line survey of 8 AGN
ID:
ivo://CDS.VizieR/J/A+A/579/A101
Title:
3mm molecular line survey of 8 AGN
Short Name:
J/A+A/579/A101
Date:
21 Oct 2021
Publisher:
CDS
Description:
We aim for a better understanding of the imprints that the nuclear activity in galaxies leaves in the molecular gas. We used the IRAM 30m telescope to observe the frequency range ~[86-116]GHz towards the central regions of the star- burst galaxies M83, M82, and NGC253, the galaxies hosting an active galactic nucleus (AGN) M51, NGC1068, and NGC7469, and the ultra-luminous infrared galaxies (ULIRGs) Arp220 and Mrk231. Assuming local thermodynamic equilibrium (LTE), we calculated the column densities of 27 molecules and 10 isotopologues (or their upper limits in case of non-detections).
1663. 1mm spectral survey of IRC+10216 & VY CMa
ID:
ivo://CDS.VizieR/J/ApJS/190/348
Title:
1mm spectral survey of IRC+10216 & VY CMa
Short Name:
J/ApJS/190/348
Date:
21 Oct 2021
Publisher:
CDS
Description:
A low noise (1{sigma}rms~3mK) 1mm spectral survey (214.5-285.5GHz) of the oxygen-rich supergiant VY Canis Majoris and the carbon-rich asymptotic giant branch star IRC +10216 has been conducted using the Arizona Radio Observatory's 10m Submillimeter Telescope. Here the complete data set is presented. This study, carried out with a new ALMA-type receiver, marks the first continuous band scan of an O-rich circumstellar envelope, and the most sensitive survey to date of IRC+10216. In VY CMa, 130 distinct molecular lines were detected, 14 of which cannot be identified; in IRC +10216, 717 lines were observed, with 126 features remaining unidentified. In the 1mm bands of VY CMa and IRC +10216, emission is present from 18 and 32 different chemical compounds, respectively, with 10 species common to both sources. Many narrow emission lines were observed in both circumstellar shells, arising from vibrationally excited molecules and from refractory-containing species. Line profiles in VY CMa also exhibit a variety of different shapes, caused by the complex, asymmetric outflow of this object.
1664. 7mm spectral survey of PKS 1830-211
ID:
ivo://CDS.VizieR/J/A+A/535/A103
Title:
7mm spectral survey of PKS 1830-211
Short Name:
J/A+A/535/A103
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a wide 7mm spectral survey of molecular absorption lines arising in the disk of a z=0.89 spiral galaxy located in front of the quasar PKS 1830-211. The survey was done with the Australia Telescope Compact Array and covers the frequency interval 30-50GHz, corresponding to the rest-frame frequency interval 57-94GHz. A total of 28 different species, plus 8 isotopic variants, were detected toward the South-West absorption, located at about 2kpc from the center of the z=0.89 galaxy, which makes it the extragalactic object with the largest number of detected molecular species so far.
1665. MMT spectra of SNRs and SNR candidates in M33
ID:
ivo://CDS.VizieR/J/ApJ/855/140
Title:
MMT spectra of SNRs and SNR candidates in M33
Short Name:
J/ApJ/855/140
Date:
21 Oct 2021
Publisher:
CDS
Description:
To date, over 220 emission nebulae in M33 have been identified as supernova remnants (SNRs) or SNR candidates, principally through [SII]:H{alpha} line ratios that are elevated compared to those in HII regions. In many cases, the determination of a high [SII]:H{alpha} line ratio was made using narrow-band interference filter images and has not been confirmed spectroscopically. Here, we present MMT 6.5m optical spectra that we use to measure [SII]:H{alpha} and other line ratios in an attempt to determine the nature of these suggested candidates. Of the 197 objects in our sample, 120 have no previously published spectroscopic observations. We confirm that the majority of candidate SNRs have emission line ratios characteristic of SNRs. While no candidates show Doppler-broadened lines expected from young, ejecta-dominated SNRs (>~1000km/s), a substantial number do exhibit lines that are broader than HII regions. We argue that the majority of the objects with high [SII]:H{alpha} line ratios (>0.4) are indeed SNRs, but the distinction between HII regions and SNRs becomes less obvious at low surface brightness, and additional criteria, such as X-ray detection, are needed. We discuss the properties of the sample as a whole and compare it with similar samples in other nearby galaxies.
1666. MMT spectroscopic redshift catalog of the A521 field
ID:
ivo://CDS.VizieR/J/ApJ/903/151
Title:
MMT spectroscopic redshift catalog of the A521 field
Short Name:
J/ApJ/903/151
Date:
21 Mar 2022 05:59:04
Publisher:
CDS
Description:
A521 has been a subject of extensive panchromatic studies from X-ray to radio. The cluster possesses a number of remarkable features, including a bright radio relic with a steep spectrum, more than three distinct galaxy groups forming a filament, and two disturbed X-ray peaks at odds with the distant position and tilted orientation of the radio relic. These lines of evidence indicate a complex merger. In this paper, we present a multiwavelength study of A521 based on Subaru optical, Hubble Space Telescope infrared, Chandra X-ray, Giant Metrewave Radio Telescope radio, and Multiple Mirror Telescope optical spectroscopic observations. Our weak-lensing (WL) analysis with improved systematics control reveals that A521 is mainly composed of three substructures aligned in the northwest to southeast orientation. These WL mass substructures are remarkably well-aligned with the cluster optical luminosity distribution constructed from our new enhanced cluster member catalog. These individual substructure masses are determined by simultaneously fitting three Navarro-Frenk-White profiles. We find that the total mass of A521 modeled by the superposition of the three halos is 13.0_-1.3_^+1.0^x10^14^M{odot}, a factor of 2 higher than the previous WL measurement. With these WL mass constraints combined with X-ray and radio features, we consider two merging scenarios, carry out the corresponding numerical simulations, and discuss the strengths and weaknesses of each case.
1667. MnI hyperfine lines in the 1.4-1.8um (H) band
ID:
ivo://CDS.VizieR/J/ApJS/216/2
Title:
MnI hyperfine lines in the 1.4-1.8um (H) band
Short Name:
J/ApJS/216/2
Date:
21 Oct 2021
Publisher:
CDS
Description:
The three Mn I lines at 17325, 17339, and 17349{AA} are among the 25 strongest lines (log(gf)>0.5) in the H band. They are all heavily broadened due to hyperfine structure, and the profiles of these lines have so far not been understood. Earlier studies of these lines even suggested that they were blended. In this work, the profiles of these three infrared (IR) lines have been studied theoretically and compared to experimental spectra to assist in the complete understanding of the solar spectrum in the IR. It is shown that the structure of these lines cannot be described in the conventional way using the diagonal A and B hyperfine interaction constants. The off-diagonal hyperfine interaction not only has a large impact on the energies of the hyperfine levels, but also introduces a large intensity redistribution among the hyperfine lines, changing the line profiles dramatically. By performing large-scale calculations of the diagonal and off-diagonal hyperfine interaction and the gf-values between the upper and lower hyperfine levels and using a semi-empirical fitting procedure, we achieved agreement between our synthetic and experimental spectra. Furthermore, we compare our results with observations of stellar spectra. The spectra of the Sun and the K1.5 III red giant star Arcturus were modeled in the relevant region, 1.73-1.74{mu}m, using our theoretically predicted gf-values and energies for each individual hyperfine line. Satisfactory fits were obtained and clear improvements were found using our new data compared with the old available Mn I data.
1668. Mock spectro-photometric catalog of galaxies
ID:
ivo://CDS.VizieR/J/A+A/504/359
Title:
Mock spectro-photometric catalog of galaxies
Short Name:
J/A+A/504/359
Date:
21 Oct 2021
Publisher:
CDS
Description:
Future dark energy space missions such as JDEM and EUCLID are being designed to survey the galaxy population to trace the geometry of the universe and the growth of structure, which both depend on the cosmological model. To reach the goal of high precision cosmology they need to evaluate the capabilities of different instrument designs based on realistic mock catalog. The aim of this paper is to construct realistic and flexible mock catalogs based on our knowledge of galaxy population from current deep surveys. We explore two categories of mock catalog : (i) based on luminosity functions fit of observations (GOODS, UDF, COSMOS, VVDS) using the Le Phare software (ii) based on the observed COSMOS galaxy distribution which benefits from all the properties of the data-rich COSMOS survey. For these two catalogs, we have produced simulated number counts in several bands, color diagrams and redshift distribution for validation against real observational data. We also derive some basic requirements to help designing future Dark Energy mission in terms of number of galaxies available for the weak-lensing analysis as a function of the PSF size and depth of the survey. We also compute the spectroscopic success rate for future spectroscopic redshift surveys (i) aiming at measuring BAO in the case of the wide field spectroscopic redshift survey, and (ii) for the photometric redshift calibration survey which is required to achieve weak lensing tomography with great accuracy. They will be publicly accessible at http://lamwws.oamp.fr/cosmowiki/RealisticSpectroPhotCat, or by request to the first author of this paper.
1669. Model atmosphere analysis of hot WDs from SDSS DR12
ID:
ivo://CDS.VizieR/J/ApJ/901/93
Title:
Model atmosphere analysis of hot WDs from SDSS DR12
Short Name:
J/ApJ/901/93
Date:
18 Feb 2022 00:21:32
Publisher:
CDS
Description:
As they evolve, white dwarfs undergo major changes in surface composition, a phenomenon known as spectral evolution. In particular, some stars enter the cooling sequence with helium atmospheres (type DO) but eventually develop hydrogen atmospheres (type DA), most likely through the upward diffusion of residual hydrogen. Our empirical knowledge of this process remains scarce: the fractions of white dwarfs that are born helium rich and that experience the DO-to-DA transformation are poorly constrained. We tackle this issue by performing a detailed model-atmosphere investigation of 1806 hot (Teff>=30000K) white dwarfs observed spectroscopically by the Sloan Digital Sky Survey. We first introduce our new generations of model atmospheres and theoretical cooling tracks, both appropriate for hot white dwarfs. We then present our spectroscopic analysis, from which we determine the atmospheric and stellar parameters of our sample objects. We find that ~24% of white dwarfs begin their degenerate life as DO stars, among which ~2/3 later become DA stars. We also infer that the DO-to-DA transition occurs at substantially different temperatures (75000K>Teff>30000K) for different objects, implying a broad range of hydrogen content within the DO population. Furthermore, we identify 127 hybrid white dwarfs, including 31 showing evidence of chemical stratification, and we discuss how these stars fit in our understanding of the spectral evolution. Finally, we uncover significant problems in the spectroscopic mass scale of very hot (Teff>60000K) white dwarfs.
1670. Model 1D (LHD) and 3D (CO5BOLD) spectra
ID:
ivo://CDS.VizieR/J/A+A/550/A103
Title:
Model 1D (LHD) and 3D (CO5BOLD) spectra
Short Name:
J/A+A/550/A103
Date:
21 Oct 2021
Publisher:
CDS
Description:
To derive space velocities of stars along the line of sight from wavelength shifts in stellar spectra requires accounting for a number of second-order effects. For most stars, gravitational redshifts, convective blueshifts, and transverse stellar motion are the dominant contributors. We provide theoretical corrections for the net velocity shifts due to convection expected for the measurements from the Gaia Radial Velocity Spectrometer (RVS). We used a set of three-dimensional time-dependent simulations of stellar surface convection computed with CO5BOLD to calculate spectra of late-type stars in the Gaia RVS range and to infer the net velocity offset that convective motions will induce in radial velocities derived by cross-correlation. The net velocity shifts derived by cross-correlation depend both on the wavelength range and spectral resolution of the observations. Convective shifts for Gaia RVS observations are less than 0.1km/s for late-K-type stars, and they increase with stellar mass, reaching about 0.3km/s or more for early F-type dwarfs. This tendency is the result of an increase with effective temperature in both temperature and velocity fluctuations in the line-forming region. Our simulations also indicate that the net RVS convective shifts can be positive (i.e. redshifts) in some cases. Overall, the blueshifts weaken slightly with increasing surface gravity, and are enhanced at low metallicity. Gravitational redshifts amount up to 0.7km/s and dominate convective blueshifts for dwarfs, but become much weaker for giants.

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