- ID:
- ivo://CDS.VizieR/J/AJ/152/213
- Title:
- Interferometry and spectroscopy of sigma Orionis
- Short Name:
- J/AJ/152/213
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present interferometric observations of the {sigma} Orionis triple system using the CHARA Array, NPOI, and VLTI. Using these measurements, we spatially resolve the orbit of the close spectroscopic binary (Aa,Ab) for the first time and present a revised orbit for the wide pair (A,B). Combining the visual orbits with previously published radial velocity measurements and new radial velocities measured at CTIO, we derive dynamical masses for the three massive stars in the system of M_Aa_=16.99+/-0.20M_{Sun}_, M_Ab_=12.81+/-0.18M_{Sun}_, and M_B_=11.5+/-1.2M_{Sun}_. The inner and outer orbits in the triple are not coplanar, with a relative inclination of 120{deg}-127{deg}. The orbital parallax provides a precise distance of 387.5+/-1.3pc to the system. This is a significant improvement over previous estimates of the distance to the young {sigma} Orionis cluster.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/493/2339
- Title:
- Internal motions in OB-associations
- Short Name:
- J/MNRAS/493/2339
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the motions inside 28 OB-associations with the use of Gaia DR2 proper motions. The average velocity dispersion calculated for 28 OB-associations including more than 20 stars with Gaia DR2 proper motion is sigma_v_=4.5km/s. The median virial and stellar masses of OB-associations are 8.9x10^5^ and 8.1x10^3^M_{sun}_, respectively. The median star-formation efficiency in parent giant molecular clouds appears to be epsilon=1.2%. Gaia DR2 proper motions confirm the expansion in the Per OB1, Car OB1 and Sgr OB1 associations found earlier with Gaia DR1 data. We also detect the expansion in Gem OB1, Ori OB1 and Sco OB1 associations which became possible for the first time now when analyzed with Gaia DR2 proper motions. The analysis of the distribution of OB-stars in the Per OB1 association shows the presence of a shell-like structure with the radius of 40 pc. Probably, the expansion of the Per OB1 association started with the velocity greater than the present-day expansion velocity equal to 5.0+/-1.7km/s.
- ID:
- ivo://CDS.VizieR/J/AJ/127/3456
- Title:
- Internal velocities in the Orion Nebula
- Short Name:
- J/AJ/127/3456
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A map of high-velocity features in the 3'x5' central region of the Orion Nebula was created from slit spectra with a velocity resolution of 8km/s. Spatial velocities of 19 features belonging to 11 HH objects were obtained by combining these radial velocity data with existing proper motion data.
- ID:
- ivo://CDS.VizieR/J/ApJS/145/355
- Title:
- Interstellar NaI lines toward anticenter
- Short Name:
- J/ApJS/145/355
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A survey of interstellar NaI D1 and D2 absorption features in the spectra of 104 early-type stars in the second and third Galactic quadrants reveals the large-scale kinematics of the interstellar gas within the Galactic anticenter hemisphere at distances from the Sun between ~70 and ~250pc. Employing a technique that uses both the radial velocities and column densities of the NaI absorptions produced by the intervening gas we have identified the velocity vectors and determined the spatial distribution of eight interstellar clouds in the volume explored.
- ID:
- ivo://CDS.VizieR/J/AJ/116/2728
- Title:
- I photometry of early-type galaxies
- Short Name:
- J/AJ/116/2728
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As part of a project to compare the fundamental plane and Tully-Fisher distance scales, we present here I-band CCD photometry for 636 early-type galaxies in eight clusters and groups of galaxies. These are the A262, A1367, Coma (A1656), A2634, Cancer and Pegasus Clusters, and the NGC 383 and NGC 507 Groups. Sample selection, cluster properties, and cluster membership assignment criteria are discussed. We present photometric parameters that are used in the fundamental plane relation, the effective radius r_e_, and the effective surface brightness {mu}_e_, as derived from a r^1/4^ fit to the observed radial photometric profile of each galaxy. A comparison with similar data found in the literature for the Coma Cluster shows that large systematic uncertainties can be introduced in the measurement of r_e_ and {mu}_e_ by the particular method used to derive those parameters. However, the particular combination of these two parameters that enters in the fundamental plane relation is a quantity that can be measured with high accuracy.
- ID:
- ivo://CDS.VizieR/J/A+A/635/A47
- Title:
- IRAS F08572+3915 CO(1-0) datacube
- Short Name:
- J/A+A/635/A47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To understand the role that AGN feedback plays in galaxy evolution we need in-depth studies of the multi-phase structure and energetics of galaxy-wide outflows. In this work we present new, deep (~50hr) NOEMA CO(1-0) line observations of the molecular gas in the powerful outflow driven by the AGN in the ultra-luminous infrared galaxy IRAS F08572+3915. We spatially resolve the outflow, finding that its most likely configuration is a wide-angle bicone aligned with the kinematic major axis of the rotation disk. The molecular gas in the wind reaches velocities up to approximately +/-1200km/s and transports nearly 20% of the molecular gas mass in the system. We detect a second outflow component located 6 kpc north-west from the galaxy moving away at 900km/s, which could be the result of a previous episode of AGN activity. The total mass and energetics of the outflow, which includes contributions from the ionized, neutral, warm and cold molecular gas phases is strongly dominated by the cold molecular gas. In fact, the molecular mass outflow rate is higher than the star formation rate, even if we only consider the gas in the outflow that is fast enough to escape the galaxy, which accounts for about 40% of the total mass of the outflow. This results in an outflow depletion time for the molecular gas in the central ~1.5kpc region of only ~3Myr, a factor of ~2 shorter than the depletion time by star formation activity.
- ID:
- ivo://CDS.VizieR/J/ApJS/89/57
- Title:
- IRAS galaxies behind southern Milky Way
- Short Name:
- J/ApJS/89/57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We systematically searched for IRAS galaxies with 60nm flux density larger than 0.6Jy by using the UK Schmidt Infrared and IIIa-J Atlases in the Milky Way region (|b|<15{deg}) between l=210{deg} and 360{deg}. We first selected about 4000 IRAS point sources by using our far-infrared criteria, which are optimized for the search of IRAS galaxies behind the Milky Way region, and then inspected visually the optical counterparts of them on the Schmidt Atlas film copies. We found 966 IRAS sources associated with galaxy-like objects. The list of the objects is presented here with the IRAS source name, Galactic coordinates, IRAS flux densities, field number and emulsion of the Atlas, type and size of galaxy(-like) image, redshift, multiplicity, and cross-identification. Of these, 423 galaxies are already catalogued in the Catalog of Galaxies and Quasars Observed in the IRAS Survey (Cat. <VII/113>), and most of the remaining 543 galaxy candidates are newly identified in this search. Although the radial velocities are known for only 387 galaxies, of which 60 were newly measured by us so far, we inferred the contamination by Galactic objects to be small from the good correlation between the sky distributions of the newly identified galaxy candidates and the previously catalogued galaxies. In the regions where the Galactic molecular clouds dominate, almost all the sources were not identified as galaxies. The detected galaxies are clustered in the three regions around l=240{deg}, 280{deg}, and 315{deg}, where the projected number densities are higher than the whole-sky average of IRAS galaxies of the same flux limit.
- ID:
- ivo://CDS.VizieR/J/ApJ/801/69
- Title:
- Iron EWs for 21 giant star members of NGC3201
- Short Name:
- J/ApJ/801/69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 3201 is a globular cluster suspected to have an intrinsic spread in the iron content. We re-analyzed a sample of 21 cluster stars observed with UVES-FLAMES at the Very Large Telescope and for which Simmerer et al. (2013ApJ...764L...7S) found a 0.4dex wide [Fe/H] distribution with a metal-poor tail. We confirmed that when spectroscopic gravities are adopted, the derived [Fe/H] distribution spans ~0.4dex. On the other hand, when photometric gravities are used, the metallicity distribution from Fe I lines remains large, while that derived from Fe II lines is narrow and compatible with no iron spread. We demonstrate that the metal-poor component claimed by Simmerer et al. (2013ApJ...764L...7S) is composed by asymptotic giant branch stars that could be affected by non-local thermodynamical equilibrium effects driven by iron overionization. This leads to a decrease of the Fe I abundance, while leaving the Fe II abundance unaltered. A similar finding has been already found in asymptotic giant branch stars of the globular clusters M5 and 47 Tucanae. We conclude that NGC 3201 is a normal cluster, with no evidence of intrinsic iron spread.
- ID:
- ivo://CDS.VizieR/J/ApJ/722/1226
- Title:
- IR photometry in {lambda} Orionis cluster
- Short Name:
- J/ApJ/722/1226
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present IRAC/MIPS Spitzer Space Telescope observations of the solar-type and the low-mass stellar population of the young (~5Myr) {lambda} Orionis cluster. Combining optical and Two Micron All Sky Survey photometry, we identify 436 stars as probable members of the cluster. Given the distance (450pc) and the age of the cluster, our sample ranges in mass from 2M_{sun}_ to objects below the substellar limit. With the addition of the Spitzer mid-infrared data, we have identified 49 stars bearing disks in the stellar cluster. Using spectral energy distribution slopes, we place objects in several classes: non-excess stars (diskless), stars with optically thick disks, stars with "evolved disks" (with smaller excesses than optically thick disk systems), and "transitional disk" candidates (in which the inner disk is partially or fully cleared). The disk fraction depends on the stellar mass, ranging from ~6% for K-type stars (R_C_-J<2) to ~27% for stars with spectral-type M5 or later (R_C_-J>4). We confirm the dependence of disk fraction on stellar mass in this age range found in other studies. Regarding clustering levels, the overall fraction of disks in the {lambda} Orionis cluster is similar to those reported in other stellar groups with ages normally quoted as ~5Myr.
- ID:
- ivo://CDS.VizieR/J/ApJS/226/11
- Title:
- IR spectroscopy of AGN & starbursts
- Short Name:
- J/ApJS/226/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A sample of 379 extragalactic sources is presented that has mid-infrared, high-resolution spectroscopy from the Spitzer Infrared Spectrograph (IRS) and also spectroscopy of the [CII]158{mu}m line from the Herschel Photodetector Array Camera and Spectrometer (PACS). The emission line profiles of [NeII]12.81{mu}m, [NeIII]15.55{mu}m, and [CII]158{mu}m are presented, and intrinsic line widths are determined (full width half maximum of Gaussian profiles after instrumental correction). All line profiles, together with overlays comparing the positions of PACS and IRS observations, are made available in the Cornell Atlas of Spitzer IRS Sources (CASSIS). Sources are classified from active galactic nucleus (AGN) to starburst based on equivalent widths of the 6.2{mu}m polycyclic aromatic hydrocarbon feature. It is found that intrinsic line widths do not change among classifications for [CII], with median widths of 207km/s for AGNs, 248km/s for composites, and 233km/s for starbursts. The [NeII] line widths also do not change with classification, but [NeIII] lines are progressively broader from starburst to AGN. A few objects with unusually broad lines or unusual redshift differences in any feature are identified.