- ID:
- ivo://CDS.VizieR/J/ApJS/180/117
- Title:
- MK classifications of spectroscopic binaries
- Short Name:
- J/ApJS/180/117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New MK spectral classifications are given for 145 spectroscopic binaries (SBs) with A-F primaries because two-dimensional types are lacking for more than one-third of the A-F SBs with known orbital elements in the current catalog. Compared with the classifications by Morgan, Keenan, and their students, the new classifications give types that are 1.1+/-0.2 subclasses later and 0.7+/-0.1 luminosity classes fainter. Also listed are selected published MK types from Brian Skiff's recent compilation (Cat. <B/mk>).
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- ID:
- ivo://CDS.VizieR/J/A+A/623/A171
- Title:
- Mkn 848 MaNGA 3-D data cube
- Short Name:
- J/A+A/623/A171
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The characterisation of galaxy-scale outflows in terms of their multi-phase and multi-scale nature, amount, and effects of flowing material is crucial to place constraints on models of galaxy formation and evolution. This study can proceed only with the detailed investigation of individual targets. We present a spatially resolved spectroscopic optical data analysis of Mkn 848, a complex system consisting of two merging galaxies at z~0.04 that are separated by a projected distance of 7.5kpc. Motivated by the presence of a multi-phase outflow in the north-west system revealed by the SDSS integrated spectrum, we analysed the publicly available MaNGA data, which cover almost the entire merging system, to study the kinematic and physical properties of cool and warm gas in detail. Galaxy-wide outflowing gas in multiple phases is revealed for the first time in the two merging galaxies. We also detect spatially resolved resonant NaID emission associated with the outflows. The derived outflow energetics (mass rate, and kinetic and momentum power) may be consistent with a scenario in which both winds are accelerated by stellar processes and AGN activity, although we favour an AGN origin given the high outflow velocities and the ionisation conditions observed in the outflow regions. Further deeper multi-wavelength observations are required, however, to better constrain the nature of these multi-phase outflows. Outflow energetics in the north-west system are strongly different between the ionised and atomic gas components, the latter of which is associated with mass outflow rate and kinetic and momentum powers that are one or two dex higher; those associated with the south-east galaxy are instead similar. Strong kiloparsec-scale outflows are revealed in an ongoing merger system, suggesting that feedback can potentially impact the host galaxy even in the early merger phases. The characterisation of the neutral and ionised gas phases has proved to be crucial for a comprehensive study of the outflow phenomena.
- ID:
- ivo://CDS.VizieR/J/A+A/592/A51
- Title:
- 3mm and 1mm spectra of IRC +10420
- Short Name:
- J/A+A/592/A51
- Date:
- 24 Nov 2021 07:04:25
- Publisher:
- CDS
- Description:
- Our knowledge of the chemical properties of the circumstellar ejecta of the most massive evolved stars is particularly poor. We aim to study the chemical characteristics of the prototypical yellow hypergiant star, IRC +10420. For this purpose, we obtained full line surveys at 1 and 3mm atmospheric windows. We have identified 106 molecular emission lines from 22 molecular species. Approximately half of the molecules detected are N-bearing species, in particular HCN, HNC, CN, NO, NS, PN, and N_2_H. We used rotational diagrams to derive the density and rotational temperature of the different molecular species detected. We introduced an iterative method that allows us to take moderate line opacities into account.
- ID:
- ivo://CDS.VizieR/J/A+A/604/A78
- Title:
- M17 massive pms stars X-shooter spectra
- Short Name:
- J/A+A/604/A78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The formation process of massive stars is still poorly understood. Massive young stellar objects (mYSOs) are deeply embedded in their parental clouds; these objects are rare, and thus typically distant, and their reddened spectra usually preclude the determination of their photospheric parameters. M17 is one of the best-studied HII regions in the sky, is relatively nearby, and hosts a young stellar population. We have obtained optical to near-infrared spectra of previously identified candidate mYSOs and a few OB stars in this region with X-shooter on the ESO Very Large Telescope. The large wavelength coverage enables a detailed spectroscopic analysis of the photospheres and circumstellar disks of these candidate mYSOs. We confirm the pre-main-sequence (PMS) nature of six of the stars and characterise the O stars. The PMS stars have radii that are consistent with being contracting towards the main sequence and are surrounded by a remnant accretion disk. The observed infrared excess and the double-peaked emission lines provide an opportunity to measure structured velocity profiles in the disks. We compare the observed properties of this unique sample of young massive stars with evolutionary tracks of massive protostars and propose that these mYSOs near the western edge of the HII region are on their way to become main-sequence stars (~6-20M_{sun}_) after having undergone high mass accretion rates (dMacc/dt~10^-4^-10^-3^M_{sun}_/yr) Their spin distribution upon arrival at the zero age main-sequence (ZAMS) is consistent with that observed for young B stars, assuming conservation of angular momentum and homologous contraction.
- 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).
- 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.
- 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.
- 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.
- ID:
- ivo://CDS.VizieR/J/A+A/574/A108
- Title:
- Molecular absorption lines in PKS 1830-211
- Short Name:
- J/A+A/574/A108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on measurements with the Effelsberg 100-m telescope, a multiline study of molecular species is presented toward the southwestern source of the gravitational lens system PKS 1830-211, which is by far the best known target for studying molecular gas in absorption at intermediate redshift. Determining line parameters and optical depths and performing large velocity gradient radiative transfer calculations, the aims of this study are (1) to evaluate physical parameters of the absorbing foreground gas at z~0.89, in particular its homogeneity, and (2) to monitor the spectroscopic time variability caused by fluctuations in the z~2.5 background continuum source.
- ID:
- ivo://CDS.VizieR/J/other/RAA/20.115
- Title:
- Molecular clumps CO, HCO and HCN data
- Short Name:
- J/other/RAA/20.1
- Date:
- 19 Jan 2022 00:26:13
- Publisher:
- CDS
- Description:
- Gravitational accretion accumulates the original mass. This process is crucial for us to understand the initial phases of star formation. Using the specific infall profiles in optically thick and thin lines, we searched the clumps with infall motion from the Milky Way Imaging Scroll Painting (MWISP) CO data in previous work. In this study, we selected 133 sources as a sub-sample for further research and identification. The excitation temperatures of these sources are between 7.0 and 38.5K, while the H_2_ column densities are between 10^21^ and 10^23^cm^-2^. We have observed optically thick lines HCO+(1-0) and HCN(1-0) using the DLH 13.7-m telescope, and found 56 sources with a blue profile and no red profile in these two lines, which are likely to have infall motions, with a detection rate of 42%. This suggests that using CO data to restrict the sample can effectively improve the infall detection rate. Among these confirmed infall sources are 43 associated with Class 0/I young stellar objects (YSOs), and 13 which are not. These 13 sources are probably associated with the sources in the earlier evolutionary stage. In comparison, the confirmed sources that are associated with Class 0/I YSOs have higher excitation temperatures and column densities, while the other sources are colder and have lower column densities. Most infall velocities of the sources that we confirmed are between 10^-1^ to 100km/s, which is consistent with previous studies.
