- ID:
- ivo://CDS.VizieR/J/AJ/137/3149
- Title:
- Near-infrared imaging polarimetry in S106
- Short Name:
- J/AJ/137/3149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of wide-field JHKS polarimetry toward the HII region S106 using the Infrared Survey Facility telescope. Our polarimetry data revealed an extended (up to ~5') polarized nebula over S106. We confirmed the position of the illuminating source of most of the nebula as consistent with S106 IRS 4 through an analysis of polarization vectors. The bright portion of the polarized intensity is consistent with the red wing component of the molecular gas.
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- ID:
- ivo://CDS.VizieR/J/A+A/553/A48
- Title:
- Near-infrared variability in RCW 38
- Short Name:
- J/A+A/553/A48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We want to study the content of young stellar objects in the RCW 38 cluster by means of multi-epoch variability studies. We performed a three-month near-infrared (NIR) monitoring campaign of the young cluster RCW 38 using the 80cm IRIS telescope near Cerro Armazones, Chile. Variability data with a median sampling of 1 day was gathered for 1026 sources, while a total of 3433 sources in JHK could be studied in the co-added, deep images with a completeness limit of K<15mag.
- ID:
- ivo://CDS.VizieR/J/MNRAS/414/1526
- Title:
- Near-IR photometry of Sh 2-235
- Short Name:
- J/MNRAS/414/1526
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Spitzer-Infrared Array Camera (IRAC) images of the S235 star-forming complex that includes the east 1, east 2, central, S235A and S235B regions. In addition, we present the near-infrared images of the S235A and S235B regions. The IRAC photometry reveals on-going star formation, with 86 Class 0/I and 144 Class II young stellar objects (YSOs) in the entire S235 complex.
- ID:
- ivo://CDS.VizieR/J/ApJ/693/430
- Title:
- Near-IR photometry of Sh2-157 and Sh2-152
- Short Name:
- J/ApJ/693/430
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Near-infrared JHK' and H_2_{nu}=1-0S(1) imaging observations of the star-forming regions Sh2-157 and Sh2-152 are presented. The data reveal a cluster of young stars associated with H_2_ line emission in each region. Additionally, many IR point sources are found in the dense core of each molecular cloud. Most of these sources exhibit infrared color excesses typical of T Tauri stars, Herbig Ae/Be stars, and protostars. Several display the characteristics of massive stars. We calculate histograms of the K'-magnitude and [H-K'] color for all sources, as well as two-color and color-magnitude diagrams. The stellar populations inside and outside the clusters are similar, suggesting that these systems are rather evolved. Shock-driven H_2_ emission knots are also detected, which may be related to evident subclusters in an earlier evolutionary stage.
- ID:
- ivo://CDS.VizieR/J/A+A/591/A74
- Title:
- Nebular emission lines towards NGC3372 center
- Short Name:
- J/A+A/591/A74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present observations from the Gaia-ESO Survey in the lines of H{alpha}, [NII], [SII], and He I of nebular emission in the central part of the Carina nebula. We investigate the properties of the two already known kinematic components (approaching and receding), which account for the bulk of emission. Moreover, we investigate the features of the much less known low-intensity high-velocity (absolute RV>50km/s) gas emission. We show that gas giving rise to H{alpha} and HeI emission is dynamically well correlated with but not identical to gas seen through forbidden-line emission. Gas temperatures are derived from line-width ratios, and densities from [SII] doublet ratios. The spatial variation of N ionization is also studied, and found to differ between the approaching and receding components. The main result is that the bulk of the emission lines in the central part of Carina arise from several distinct shell-like expanding regions, the most evident found around {eta} Car, the Trumpler 14 core, and the star WR25. These "shells" are non-spherical and show distortions probably caused by collisions with other shells or colder, higher-density gas. Some of them are also partially obscured by foreground dust lanes, while very little dust is found in their interior. Preferential directions, parallel to the dark dust lanes, are found in the shell geometries and physical properties, probably related to strong density gradients in the studied region. We also find evidence that the ionizing flux emerging from {eta} Car and the surrounding Homunculus nebula varies with polar angle. The high-velocity components in the wings of H{alpha} are found to arise from expanding dust reflecting the {eta} Car spectrum.
- ID:
- ivo://CDS.VizieR/J/ApJ/755/90
- Title:
- [NeII] emission line observations from SgrA West
- Short Name:
- J/ApJ/755/90
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new observations of the [NeII] emission from the ionized gas in Sgr A West with improved resolution and sensitivity. About half of the emission comes from gas with kinematics indicating it is orbiting in a plane tipped about 25{deg} from the Galactic plane. This plane is consistent with that derived previously for the circumnuclear molecular disk and the northern arm and western arc ionized features. However, unlike most previous studies, we conclude that the ionized gas is not moving along the ionized features, but on more nearly circular paths. The observed speeds are close to, but probably somewhat less than expected for orbital motions in the potential of the central black hole and stars and have a small inward component. The spatial distribution of the emission is well fitted by a spiral pattern. We discuss possible physical explanations for the spatial distribution and kinematics of the ionized gas, and conclude that both may be best explained by a one-armed spiral density wave, which also accounts for both the observed low velocities and the inward velocity component. We suggest that a density wave may result from the precession of elliptical orbits in the potential of the black hole and stellar mass distribution.
- ID:
- ivo://CDS.VizieR/J/A+AS/114/215
- Title:
- New SNR candidates in M31
- Short Name:
- J/A+AS/114/215
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed a CCD H{alpha}, [SII], V survey of ~1.0 square degree of the disk of M 31 to search for new supernova remnant (SNR) candidates. We have identified candidates based on a combination of criteria: optical line-flux ratios, the presence or absence of ionizing blue stars, and optical morphology. We have identified a total of 178 candidate SNRs, divided into three confidence categories: 13 with the highest confidence, 54 with moderate confidence, and 111 with the lowest confidence. We have also identified 14 large structures with the characteristics of the superbubbles seen in the Galaxy and Magellanic Clouds. Of our 178 candidates, 15 have been identified in previous searches (Braun & Walterbos 1993; Blair et al. 1981; D'Odorico et al. 1980). We present finding charts of all candidate SNRs and the superbubbles we have noted. We also present a detailed discussion of SNR searches in the Local Group.
- ID:
- ivo://CDS.VizieR/J/A+A/607/A86
- Title:
- NGC 6334 and NGC 6357 OB stars spectra
- Short Name:
- J/A+A/607/A86
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The formation of high mass stars is still debated. For this reason, several projects, as the Herschel-HOBYS are focussed on the study of the earliest phases of massive star formation. As a result, massive star-forming complexes such as NGC 6334 and NGC 6357 have been observed in the far-infrared to study their massive dense cores where massive stars are expected to form. However, to better characterise the environment of these cores we need to understand the previous massive star formation history. To better characterize the environment of these massive dense cores we propose to study the previous high mass star formation and how these stars act on their environment. This study is based on spectral classification of the OB stars identified towards NGC 6334 and NGC 6357 with spectra taken with the AAOmega spectrograph on the Anglo-Australian Telescope (AAT). From the subsequent spectral classification of 109 stars across these regions we have been able to evaluate the following: distance, age, mass, global star-forming efficiency (SFE) and star-formation rate (SFR) of the regions. The physical conditions of the ionised gas for both complexes was also derived. We confirm that NGC 6334 and NGC 6357 belong to the Saggitarius-Carina arm which, in this direction, extends from 1kpc to 2.2kpc. From the location of the stars in Hertzprung-Russell diagram we show that stars older than ~10Myr are broadly spread across these complexes while younger stars are mainly located in the H ii regions and stellar clusters. Our data also suggests that some of the young stars can be considered as runaway stars. We evaluate a SFE of 0.019 and 0.021 and a SFR of 1.1x10^3^M_{sun}/Myr^ and 1.7x10^3^M_{sun}_/Myr for NGC 6334 and NGC 6357 respectively. We note that 25 OB stars have X-ray counterparts, most of them belonging to NGC 6357. This suggests that molecular clouds in NGC 6357 is more impacted by X-ray flux and stellar winds than for NGC 6334. Finally, from analysis of nebular lines (H{alpha}, [NII] and [SII]) from spectra from several regions of ionised gas, we confirm that the filaments in NGC 6357 are shock heated.
369. NGC 628 H II regions
- ID:
- ivo://CDS.VizieR/J/AJ/120/1306
- Title:
- NGC 628 H II regions
- Short Name:
- J/AJ/120/1306
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Employing deep H{alpha} narrowband imagery, we identified and measured the fluxes of 137 small H II regions in the extreme outer disk (R>=R_25_) of the nearly face-on, Sc I galaxy NGC 628. A majority of these H II regions are located in two faint, outer spiral arms visible in H I maps. The faintest H II regions that could be measured have fluxes of only a few times 10^-16^ergs/cm^2^/s, which correspond to luminosities of 10^36^ergs/s, or a fraction of the Orion Nebula luminosity. The most distant object detected is at R~27kpc from the galaxy center. The massive star formation rate, as measured from the azimuthally averaged H{alpha} flux, is consistent with a monotonic decrease as far as R~1.3R_25_ (20kpc), where there is a sharp drop. The Schmidt law for the whole disk of NGC 628 corresponds to a relatively steep power law with n=2.9+/-0.2, but it "fails" below {Sigma}gas<=4M_{sun}_/pc^2^; the index depends strongly on the CO data used. We derived the luminosity function (LF) of 598 H II regions over the whole disk, and we compared the shapes of the cumulative LFs between R>=R_25_ and R<R_25_; the LF of the outer regions is significantly steeper than that of the inner regions.
- ID:
- ivo://CDS.VizieR/J/A+AS/128/545
- Title:
- NGC 4736 HII regions fluxes
- Short Name:
- J/A+AS/128/545
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Table 3 gives a catalog of HII region positions, diameters and absolute emission line logarithmic fluxes for NGC 4736. Table 4 gives a catalog of continua logarithmic fluxes adjacent to [OII], H{beta}, [OIII], H{alpha}, [SII] and [SIII] emission lines of NGC 4736 HII regions.
