- ID:
- ivo://CDS.VizieR/J/ApJ/623/897
- Title:
- Reddening and extinction at high galactic latitude
- Short Name:
- J/ApJ/623/897
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present near-infrared (JHKL) photometry of 103 southern stars located behind translucent interstellar clouds at high Galactic latitude. Our data are combined with visual photometry and spectral type information from the literature in a detailed analysis of the wavelength dependence of interstellar extinction by dust in these high-latitude clouds. We investigate the shape of the near-infrared extinction curve and evaluate the total line-of-sight extinction (A_V_) and ratio of total-to-selective extinction (R_V_) in each line of sight.
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- ID:
- ivo://CDS.VizieR/J/A+A/592/A142
- Title:
- Reduced high-resolution HI and CO data cubes
- Short Name:
- J/A+A/592/A142
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Intermediate-velocity clouds (IVCs) are HI halo clouds that are likely related to a Galactic fountain process. In-falling IVCs are candidates for the re-accretion of matter onto the Milky Way. Aims. We study the evolution of IVCs at the disk-halo interface, focussing on the transition from atomic to molecular IVCs. We compare an atomic IVC to a molecular IVC and characterise their structural differences in order to investigate how molecular IVCs form high above the Galactic plane. With high-resolution HI observations of the Westerbork Synthesis Radio Telescope and ^12^CO(1-0) and ^13^CO(1-0) observations with the IRAM 30m telescope, we analyse the small-scale structures within the two clouds. By correlating HI and far-infrared (FIR) dust continuum emission from the Planck satellite, the distribution of molecular hydrogen (H_2_) is estimated. We conduct a detailed comparison of the HI, FIR, and CO data and study variations of the XCO conversion factor. The atomic IVC does not disclose detectable CO emission. The atomic small-scale structure, as revealed by the high-resolution HI data, shows low peak HI column densities and low HI fluxes as compared to the molecular IVC. The molecular IVC exhibits a rich molecular structure and most of the CO emission is observed at the eastern edge of the cloud. There is observational evidence that the molecular IVC is in a transient and, thus, non- equilibrium phase. The average XCO factor is close to the canonical value of the Milky Way disk. We propose that the two IVCs represent different states in a gradual transition from atomic to molecular clouds. The molecular IVC appears to be more condensed allowing the formation of H_2_ and CO in shielded regions all over the cloud. Ram pressure may accumulate gas and thus facilitate the formation of H_2_. We show evidence that the atomic IVC will evolve also into a molecular IVC in a few Myr.
- ID:
- ivo://CDS.VizieR/J/ApJS/112/109
- Title:
- Rho Oph Near-IR Positions and Photometry
- Short Name:
- J/ApJS/112/109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains the tabulated results from a three-color (JHK) near-Infrared imaging survey of the Rho Ophiuchi star-forming cloud core. The NIR imaging observations were acquired using the SQIID instrument on the Kitt Peak 1.3m telescope from June 4-10, 1993 and April 23-28, 1994. The survey covered one square degree (2.2pc by 2.2pc). The catalog contains 4495 sources with both J2000.0 and B1950.0 coordinates for each source and its J, H, and K magnitudes and/or upper their limits. The Rho Ophiuchi clouds are of great interest for star formation studies, since they include the nearest example of a currently forming star cluster. The absolute positions in RA and Dec were determined for each individual source by using a centering algorithm in the IRAF package APPHOT to obtain center positions in pixels which were then merged into a single common positional grid. Absolute stellar coordinates were determined by comparing the authors positional database with the positions of 36 HST Guide Star Catalog stars spread out over the survey field. These were used to determine a plate scale and rotation which was used to generate the final list of source positions. The position determination technique and the photometric data reduction and calibration is discussed in detail in the source reference.
- ID:
- ivo://CDS.VizieR/J/A+A/605/A82
- Title:
- Rosette Nebula globules
- Short Name:
- J/A+A/605/A82
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Rosette nebula is an HII region ionized mainly by the stellar cluster NGC 2244. Elephant trunks, globules, and globulettes are seen at the interface where the HII region and the surrounding molecular shell meet. We have observed a field in the northwestern part of the Rosette nebula where we study the small globules protruding from the shell. Our aim is to measure their properties and study their star-formation history in continuation of our earlier study of the features of the region. We imaged the region in broadband near-infrared (NIR) JsHKs filters and narrowband H_2_ 1-0 S(1), P{beta}, and continuum filters using the SOFI camera at the ESO/NTT. The imaging was used to study the stellar population and surface brightness, create visual extinction maps, and locate star formation. Mid-infrared (MIR) Spitzer IRAC and WISE and optical NOT images were used to further study the star formation and the structure of the globules. The NIR and MIR observations indicate an outflow, which is confirmed with CO observations made with APEX.
- ID:
- ivo://CDS.VizieR/J/ApJ/897/122
- Title:
- Rotational velocities for PHANGS sample of galaxies
- Short Name:
- J/ApJ/897/122
- Date:
- 11 Mar 2022
- Publisher:
- CDS
- Description:
- We present kinematic orientations and high-resolution (150pc) rotation curves for 67 main-sequence star-forming galaxies surveyed in CO (2-1) emission by PHANGS-ALMA. Our measurements are based on the application of a new fitting method tailored to CO velocity fields. Our approach identifies an optimal global orientation as a way to reduce the impact of nonaxisymmetric (bar and spiral) features and the uneven spatial sampling characteristic of CO emission in the inner regions of nearby galaxies. The method performs especially well when applied to the large number of independent lines of sight contained in the PHANGS CO velocity fields mapped at 1" resolution. The high-resolution rotation curves fitted to these data are sensitive probes of mass distribution in the inner regions of these galaxies. We use the inner slope as well as the amplitude of our fitted rotation curves to demonstrate that CO is a reliable global dynamical mass tracer. From the consistency between photometric orientations from the literature and kinematic orientations determined with our method, we infer that the shapes of stellar disks in the mass range of log(M*(M{odot}))=9.0-10.9 probed by our sample are very close to circular and have uniform thickness.
- ID:
- ivo://CDS.VizieR/J/ApJ/642/868
- Title:
- Rotation measures for 223 pulsars
- Short Name:
- J/ApJ/642/868
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The large-scale magnetic field of our Galaxy can be probed in three dimensions using Faraday rotation of pulsar signals. We report on the determination of 223 rotation measures from polarization observations of relatively distant southern pulsars made using the Parkes radio telescope.
- ID:
- ivo://CDS.VizieR/J/A+A/513/A65
- Title:
- Rotation measures in the fourth Galactic quadrant
- Short Name:
- J/A+A/513/A65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have re-examined the published rotation measures (RMs) of extragalactic point sources and pulsars with |b|<3{deg} to study the magnetic field in the fourth Galactic quadrant. We reduced the influence of structure in electron density as much as possible by excluding objects for which H{alpha}-data indicate large fluctuations in n_e_ somewhere along the line of sight. We also excluded objects for which the RM may have been significantly "corrupted" by an intervening supernova remnant. We modelled RM(l), the longitude dependence of RM of the unaffected extragalactic sources and pulsars. We assumed several geometries for the large-scale field. All but one of those are based on logarithmic spiral arms (with various pitch angles and widths), while one has circular symmetry. We also made different assumptions about the large-scale n_e_-distribution.
- ID:
- ivo://CDS.VizieR/J/A+A/549/A56
- Title:
- Rotation Measure synthesis of WSRT obs.
- Short Name:
- J/A+A/549/A56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Rotation Measure synthesis (RM synthesis) of the Westerbork Synthesis Radio Telescope (WSRT) observations at 2m wavelength of the FAN region at l=137deg, b=+7deg shows the morphology of structures in the ionized interstellar medium.
- ID:
- ivo://CDS.VizieR/J/A+A/609/A123
- Title:
- SABOCA imaging of G304.74+01.32
- Short Name:
- J/A+A/609/A123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to determine the occurrence of fragmentation into cores in the clumps of the filamentary IRDC G304.74+01.32. We also aim to determine the basic physical characteristics of the clumps and cores in G304.74. We mapped the G304.74 filament at 350 micron using the SABOCA bolometer. The new SABOCA data have a factor of 2.2 times higher resolution than our previous LABOCA 870 micron map of the cloud (9" versus 19.86"). We also employed the Herschel far-IR and submillimetre, and WISE IR imaging data available for G304.74. The WISE data allowed us to trace the IR emission of the YSOs associated with the cloud. The SABOCA 350 micron data show that G304.74 is composed of a dense filamentary structure with a mean width of only 0.18+/-0.05pc. The percentage of LABOCA clumps that are found to be fragmented into SABOCA cores is 36%+/-16%, but the irregular morphology of some of the cores suggests that this multiplicity fraction could be higher. The WISE data suggest that 65%+/-18% of the SABOCA cores host YSOs. The mean dust temperature of the clumps, derived by comparing the Herschel 250, 350, and 500 micron flux densities, was found to be 15.0+/-0.8K. The mean mass, beam-averaged H_2_ column density, and H_2_ number density of the LABOCA clumps are estimated to be 55+/-10M_{sun}_, (2.0+/-0.2)x10^22^cm^-2^, and (3.1+/-0.2)x10^4^cm^-3^. The corresponding values for the SABOCA cores are 29+/-3M_{sun}_, (2.9+/-0.3)x10^22^cm^-2^, and (7.9+/-1.2)x10^4^cm^-3^. The G304.74 filament is estimated to be thermally supercritical by a factor of >~3.5 on the scale probed by LABOCA, and by a factor of >~1.5 for the SABOCA filament. Our data strongly suggest that the IRDC G304.74 has undergone hierarchical fragmentation. On the scale where the clumps have fragmented into cores, the process can be explained in terms of gravitational Jeans instability. Besides the filament being fragmented, the finding of embedded YSOs in G304.74 indicates its thermally supercritical state, although the potential non-thermal (turbulent) motions can render the cloud a virial equilibrium system on scale traced by LABOCA. The IRDC G304.74 has a seahorse-like morphology in the Herschel images, and the filament appears to be attached by elongated, perpendicular striations. This is potentially evidence that G304.74 is still accreting mass from the surrounding medium, and the accretion process can contribute to the dynamical evolution of the main filament. One of the clumps in G304.74, IRAS 13039-6108, is already known to be associated with high-mass star formation, but the remaining clumps and cores in this filament might preferentially form low and intermediate-mass stars owing to their mass reservoirs and sizes. Besides the presence of perpendicularly oriented, dusty striations and potential embedded intermediate-mass YSOs, G304.74 is a relatively nearby (d~2.5kpc) IRDC, which makes it a useful target for future star formation studies. Owing to its observed morphology, we propose that G304.74 could be nicknamed the Seahorse Nebula. Description: The SABOCA 350 micron and LABOCA 870 micron dust continuum maps of G304.74+01.32. The data were reduced using the CRUSH-2 software
- ID:
- ivo://CDS.VizieR/J/PASP/122/683
- Title:
- SAGE-Spec Spitzer legacy program
- Short Name:
- J/PASP/122/683
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The SAGE-Spec Spitzer Legacy program is a spectroscopic follow-up to the SAGE-LMC photometric survey of the Large Magellanic Cloud carried out with the Spitzer Space Telescope. We present an overview of SAGE-Spec and some of its first results. The SAGE-Spec program aims to study the life cycle of gas and dust in the Large Magellanic Cloud and to provide information essential to the classification of the point sources observed in the earlier SAGE-LMC photometric survey. We acquired 224.6h of observations using the infrared spectrograph and the spectral energy distribution (SED) mode of the Multiband Imaging Photometer for Spitzer. The SAGE-Spec data, along with archival Spitzer spectroscopy of objects in the Large Magellanic Cloud, are reduced and delivered to the community. We discuss the observing strategy, the specific data-reduction pipelines applied, and the dissemination of data products to the scientific community. Initial science results include the first detection of an extragalactic 21um feature toward an evolved star and elucidation of the nature of disks around RV Tauri stars in the Large Magellanic Cloud. Toward some young stars, ice features are observed in absorption. We also serendipitously observed a background quasar, at a redshift of z~~0.14, which appears to be hostless.
