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1082. Molecular lines in EGOs
- ID:
- ivo://CDS.VizieR/J/ApJ/710/150
- Title:
- Molecular lines in EGOs
- Short Name:
- J/ApJ/710/150
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the first systematic survey of molecular lines (including HCO^+^(1-0) and ^12^CO, ^13^CO, C^18^O(1-0) lines at the 3mm band) toward a new sample of 88 massive young stellar object (MYSO) candidates associated with ongoing outflows (known as extended green objects or EGOs) identified from the Spitzer GLIMPSE survey in the northern hemisphere with the Purple Mountain Observatory 13.7m radio telescope. By analyzing the asymmetries of the optically thick line HCO^+^ for 69 of 72 EGOs with HCO^+^ detection, we found 29 sources with "blue asymmetric profiles" and 19 sources with "red asymmetric profiles."
- ID:
- ivo://CDS.VizieR/J/A+A/570/A51
- Title:
- Molecular lines in 4 IRCS clumps
- Short Name:
- J/A+A/570/A51
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The earliest phases of high-mass star formation are poorly understood. Aims. Our goal is to determine the physical conditions and kinematic structure of massive starforming cloud clumps. We analyse H_2_O 557GHz line profiles observed with HIFI toward four positions in two infrared-dark cloud clumps. By comparison with ground-based C_17_O, N_2_H^+^, CH_3_OH, and NH_3_ line observations, we constrain the volume density and kinetic temperature of the gas and estimate the column density and abundance of H_2_O and N_2_H^+^. The observed water lines are complex with emission and absorption components. The absorption is redshifted and consistent with a cold envelope, while the emission is interpreted as resulting from proto-stellar outflows. The gas density in the clumps is ~10^7^cm^-3^. The o-H_2_O outflow column density is 0.3-3.0x10^14^cm^-2^. The o-H_2_O absorption column density is between 1.5x10^14^ and 2.6x10^15^cm^-2^ with cold o-H_2_O abundances between 1.5x10^-9^ and 3.1x10^-8^. All clumps have high gas densities (~10^7^cm^-3^) and display infalling gas. Three of the four clumps have outflows. The clumps form an evolutionary sequence as probed by H_2_O N_2_H+, NH_3_, and CH_3_OH. We find that G28-MM is the most evolved, followed by G11-MM and then G28-NH3. The least evolved clump is G11-NH3 which shows no signposts of starformation; G11-NH3 is a high-mass pre-stellar core.
- ID:
- ivo://CDS.VizieR/J/ApJ/869/142
- Title:
- Monitoring AGNs with H{beta} Asymmetry (MAHA). I.
- Short Name:
- J/ApJ/869/142
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have started a long-term reverberation mapping (RM) project using the Wyoming Infrared Observatory 2.3m telescope titled "Monitoring AGNs with H{beta} Asymmetry" (MAHA). The motivations of the project are to explore the geometry and kinematics of the gas responsible for complex H{beta} emission-line profiles, ideally leading to an understanding of the structures and origins of the broad-line region (BLR). Furthermore, such a project provides the opportunity to search for evidence of close binary supermassive black holes. We describe MAHA and report initial results from our first campaign, from 2016 December to 2017 May, highlighting velocity-resolved time lags for four active galactic nuclei (AGNs) with asymmetric H{beta} lines. We find that 3C120, Ark120, and Mrk6 display complex features different from the simple signatures expected for pure outflow, inflow, or a Keplerian disk. While three of the objects have been previously reverberation mapped, including velocity-resolved time lags in the cases of 3C120 and Mrk6, we report a time lag and corresponding black hole mass measurement for SBS1518+593 for the first time. Furthermore, SBS1518+593, the least asymmetric of the four, does show velocity-resolved time lags characteristic of a Keplerian disk or virialized motion more generally. Also, the velocity-resolved time lags of 3C120 have significantly changed since previously observed, indicating an evolution of its BLR structure. Future analyses of the data for these objects and others in MAHA will explore the full diversity of H{beta} lines and the physics of AGN BLRs.
- ID:
- ivo://CDS.VizieR/J/A+A/655/A4
- Title:
- MONOS II. SB1 Orbital review and analysis
- Short Name:
- J/A+A/655/A4
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Massive stars are a key element to understand the chemical and dynamical evolution of galaxies. Stellar evolution is conditioned by many factors: rotation, mass loss, and interaction with other objects are the most important ones for massive stars. During the first evolutionary stages of stars with initial masses (i.e. M_ZAMS_) in the M_ZAMS_~18-70M_{sum}_ range they are of spectral type O. Given that stars in this mass range spend roughly 90% of their lifetime as O-type stars, establishing the multiplicity frequency and binary properties of O-type stars is crucial for many fields of modern astrophysics. The aim of the MONOS project is to collect information to study Northern Galactic O-type spectroscopic binaries. In this second paper, we tackle the study of the 35 single line spectroscopic binary (SB1) systems identified in the previous paper of the series Maiz Apellaniz et al., (2019, Cat. J/A+A/626/A20) analyze our data, and review the literature on the orbits of the systems. We have measured ~4500 radial velocities for a selection of diagnostic lines for the ~700 spectra of the studied systems in our database, for which we have used two different methods: Gaussian fit for several lines per object and cross-correlation with synthetic spectra computed with the FASTWIND stellar atmospheric code. We have also explored the photometric data delivered by the TESS mission to analyze the light-curve (LC) of the systems extracting 31 of them. We have explored the possible periods with the Lomb-Scargle method and, whenever possible, calculated the orbital solutions using the SBOP&GBART codes. For those systems in which an improved solution was possible we have merged our RVs with those in the literature and calculated a combined solution. As a result of this work, of the 35 SB1 systems identified in MONOS I, we have confirmed 21 systems as SB1 with good orbits, discarded the binary nature of 6 stars (9 Sge, HD 192281, HDE 229232 AB, 68 Cyg, HD 108 and {alpha} Cam), and left 6 stars as inconclusive due to lack of data. The remaining two stars are 15 Mon Aa which has been classified as SB2 and Cyg OB2-22 C for which we find evidence that it is most likely a triple system where the O star is orbiting an eclipsing SB1. We have also recalculated 20 new orbital solutions, including the first spectroscopic orbital solution for V747 Cep. For Cyg OB2-22 C we have obtained new ephemerides but no new orbit.
- ID:
- ivo://CDS.VizieR/J/A+A/626/A20
- Title:
- MONOS. I. Spectral classifications
- Short Name:
- J/A+A/626/A20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Multiplicity in massive stars is a key element to understand the chemical and dynamical evolution of galaxies. Among massive stars, those of O type play a crucial role due to their high masses and short lifetimes. MONOS (Multiplicity Of Northern O-type Spectroscopic systems) is a project designed to collect information and study O-type spectroscopic binaries with {delta}>20{deg}. In this first paper we describe the sample and provide spectral classifications and additional information for objects with previous spectroscopic and/or eclipsing binary orbits. In future papers we will test the validity of previous solutions and calculate new spectroscopic orbits. The spectra in this paper have two sources: the Galactic O-Star Spectroscopic Survey (GOSSS), a project that is obtaining blue-violet R~2500 spectroscopy of thousands of massive stars, and LiLiMaRlin, a library of libraries of high-resolution spectroscopy of massive stars obtained from four different surveys (CAFE-BEANS, OWN, IACOB, and NoMaDS) and additional data from our own observing programs and public archives. We also use lucky images obtained with AstraLux. We present homogeneous spectral classifications for 92 O-type spectroscopic multiple systems and ten optical companions, many of them original.We discuss the visual multiplicity of each system with the support of AstraLux images and additional sources. For eleven O-type objects and for six B-type objects we present their first GOSSS spectral classifications. For two known eclipsing binaries we detect double absorption lines (SB2) or a single moving line (SB1) for the first time, to which we add a third system already reported by us recently. For two previous SB1 systems we detect their SB2 nature for the first time and give their first separate spectral classifications, something we also do for a third object just recently identified as a SB2. We also detect nine new astrometric companions and provide updated information on several others. We emphasize the results for two stars: for {sigma} Ori AaAbB we provide spectral classifications for the three components with a single observation for the first time thanks to a lucky spectroscopy observation obtained close to the Aa,Ab periastron and for {theta}^1^ Ori CaCb we add it to the class of Galactic Of?p stars, raising the number of its members to six. Our sample of O-type spectroscopic binaries contains more triple- or higher-order systems than double systems.
- ID:
- ivo://CDS.VizieR/J/ApJ/698/1682
- Title:
- Most luminous dusty galaxies
- Short Name:
- J/ApJ/698/1682
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A summary of mid-infrared continuum luminosities arising from dust is given for very luminous galaxies, L_IR_>10^12^L_{sun}_, with 0.005<z<3.2 containing active galactic nuclei (AGNs), including 115 obscured AGNs and 60 unobscured (type 1) AGNs. All sources have been observed with the Spitzer Infrared Spectrograph. Obscured AGNs are defined as having optical depth {tau}>0.7 in the 9.7um silicate absorption feature (i.e., half of the continuum is absorbed) and having equivalent width of the 6.2um polycyclic aromatic hydrocarbon feature <0.1um (to avoid sources with a significant starburst component). Unobscured AGNs are defined as those that show silicate in emission. Luminosity {nu}L_{nu}_(8um) for the most luminous obscured AGNs is found to scale as (1+z)^2.6^ to z=2.8. For unobscured AGNs, the scaling with redshift is similar, but luminosities {nu}L_{nu}_(8um) are approximately three times greater for the most luminous sources. Using both obscured and unobscured AGNs having total infrared fluxes from the Infrared Astronomical Satellite, empirical relations are found between {nu}L_{nu}_(8um) and L_IR_.
- ID:
- ivo://CDS.VizieR/J/ApJ/886/40
- Title:
- Most luminous SPIRITS IR transients follow-up obs.
- Short Name:
- J/ApJ/886/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a systematic study of the most luminous (MIR [Vega magnitudes] brighter than -14) infrared (IR) transients discovered by the SPitzer InfraRed Intensive Transients Survey (SPIRITS) between 2014 and 2018 in nearby galaxies (D<35Mpc). The sample consists of nine events that span peak IR luminosities of M_[4.5],peak_ between -14 and -18.2, show IR colors between 0.2<([3.6]-[4.5])<3.0, and fade on timescales between 55d<t_fade_<480d. The two reddest events (A_V_>12) show multiple, luminous IR outbursts over several years and have directly detected, massive progenitors in archival imaging. With analyses of extensive, multiwavelength follow-up, we suggest the following possible classifications: five obscured core-collapse supernovae (CCSNe), two erupting massive stars, one luminous red nova, and one intermediate-luminosity red transient. We define a control sample of all optically discovered transients recovered in SPIRITS galaxies and satisfying the same selection criteria. The control sample consists of eight CCSNe and one Type Iax SN. We find that 7 of the 13 CCSNe in the SPIRITS sample have lower bounds on their extinction of 2<A_V_<8. We estimate a nominal fraction of CCSNe in nearby galaxies that are missed by optical surveys as high as 38.5_-21.9_^+26.0^% (90% confidence). This study suggests that a significant fraction of CCSNe may be heavily obscured by dust and therefore undercounted in the census of nearby CCSNe from optical searches.
- ID:
- ivo://CDS.VizieR/J/A+A/483/903
- Title:
- Mount Wilson index for main sequence F-K stars
- Short Name:
- J/A+A/483/903
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The largest dataset of stellar activity measurements available at present is the one obtained at the Mount Wilson Observatory, where high-precision CaII H+K fluxes have been measured from 1966 for about 2200 stars. Since the MgII H and K lines at {lambda}2800{AA} are formed in a similar way to the CaII H+K emission lines, they are also good indicators of chromospheric structure. The International Ultraviolet Explorer (IUE) provides a large database of UV spectra in the band 1150-3350{AA} from 1978 to 1995, which can also be used to study stellar activity. The main purpose of this study is to use the IUE spectra in the analysis of magnetic activity of main sequence F-K stars. Combining IUE observations of MgII and optical spectroscopy of CaII, the registry of activity of stars can be extended in time.
- ID:
- ivo://CDS.VizieR/J/AJ/124/234
- Title:
- M31 outer halo UBVRI photometry and metallicity
- Short Name:
- J/AJ/124/234
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present first results from a spectroscopic survey designed to examine the metallicity and kinematics of individual red giant branch stars in the outer halo of the Andromeda spiral galaxy (M31). This study is based on multislit spectroscopy with the Keck II 10m telescope and Low Resolution Imaging Spectrograph of the Ca II near-infrared triplet in 99 M31 halo candidates in a field at R=19kpc on the southeast minor axis with brightnesses from 20<I<22.
