- ID:
- ivo://CDS.VizieR/J/MNRAS/392/1403
- Title:
- GMRT radios sources around J0916+6348 field
- Short Name:
- J/MNRAS/392/1403
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep multifrequency observations using the Giant Metrewave Radio Telescope (GMRT) at 153, 244, 610 and 1260MHz of a field centred on J0916+6348, to search for evidence of fossil radio lobes which could be due to an earlier cycle of episodic activity of the parent galaxy, as well as haloes and relics in clusters of galaxies. We do not find any unambiguous evidence of episodic activity in a list of 374 sources, suggesting that such activity is rare even in relatively deep low-frequency observations. We examine the spectra of all the sources by combining our observations with those from the Westerbork Northern Sky Survey (WENSS), NRAO (National Radio Astronomy Observatories) VLA (Very Large Array) Sky Survey (NVSS) and the Faint Images of the Radio Sky at Twenty-Centimeters Survey (FIRST).
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- ID:
- ivo://CDS.VizieR/J/A+A/597/A80
- Title:
- GMVA 86GHz images of OJ 287
- Short Name:
- J/A+A/597/A80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The gamma-ray BL Lac object OJ 287 is known to exhibit inner-parsec "jet-wobbling", high degrees of variability at all wavelengths and quasi-stationary features, including an apparent (~100{deg}) position-angle change in projection on the sky plane. Sub-50 micro-arcsecond resolution 86GHz observations with the global mm-VLBI array (GMVA) supplement ongoing multifrequency VLBI blazar monitoring at lower frequencies. Using these maps, together with cm/mm total intensity and gamma-ray observations from Fermi/LAT from 2008-2014, we aim to determine the location of gamma-ray emission and to explain the inner-mas structural changes. Observations with the GMVA offset approximately double the angular resolution compared with 43GHz VLBA observations and enable us to observe above the synchrotron self-absorption peak frequency. Fermi-LAT gamma-ray data were reduced and analysed. The jet was spectrally decomposed at multiple locations along the jet. From this, we could derive estimates of the magnetic field using equipartition and synchrotron self-absorption arguments. How the field decreases down the jet provided an estimate of the distance to the jet apex and an estimate of the magnetic field strength at the jet apex and in the broad line region. Combined with accurate kinematics, we attempt to locate the site of gamma-ray activity, radio flares, and spectral changes.
- ID:
- ivo://CDS.VizieR/J/A+A/622/A196
- Title:
- GMVA 86GHz Stokes IQU images of 3C84 jet
- Short Name:
- J/A+A/622/A196
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report results from a deep polarization imaging of the nearby radio galaxy 3C 84 (NGC 1275). The source was observed with the Global Millimeter VLBI Array (GMVA) at 86GHz at an ultrahigh angular resolution of 50{mu}as (corresponding to 200Rs). We also add complementary multiwavelength data from the Very Long Baseline Array (VLBA; 15 & 43GHz) and from the Atacama Large Millimeter/submillimeter Array (ALMA; 97.5, 233.0, and 343.5GHz). At 86GHz, we measured a fractional linear polarization of ~2% in the VLBI core region. The polarization morphology suggests that the emission is associated with an underlying limb-brightened jet. The fractional linear polarization is lower at 43 and 15GHz (~0.3-0.7% and <0.1%, respectively). This suggests an increasing linear polarization degree toward shorter wavelengths on VLBI scales. We also obtain a large rotation measure (RM) of ~10^5-6^rad/m^2^ in the core at >~43GHz. Moreover, the VLBA 43GHz observations show a variable RM in the VLBI core region during a small flare in 2015. Faraday depolarization and Faraday conversion in an inhomogeneous and mildly relativistic plasma could explain the observed linear polarization characteristics and the previously measured frequency dependence of the circular polarization. Our Faraday depolarization modeling suggests that the RM most likely originates from an external screen with a highly uniform RM distribution. To explain the large RM value, the uniform RM distribution, and the RM variability, we suggest that the Faraday rotation is caused by a boundary layer in a transversely stratified jet. Based on the RM and the synchrotron spectrum of the core, we provide an estimate for the magnetic field strength and the electron density of the jet plasma.
- ID:
- ivo://CDS.VizieR/J/A+A/569/A11
- Title:
- G35.20-0.74N continuum and line data cubes
- Short Name:
- J/A+A/569/A11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The formation process of high-mass stars (with masses >8M_{sun}_) is still poorly understood, and represents a challenge from both the theoretical and observational points of view. The advent of the Atacama Large Millimeter Array (ALMA) is expected to provide observational evidence to better constrain the theoretical scenarios. The present study aims at characterizing the high-mass star forming region G35.20-0.74N, which is found associated with at least one massive outflow and contains multiple dense cores, one of them recently found associated with a Keplerian rotating disk. We used the radio-interferometer ALMA to observe the G35.20-0.74N region in the submillimeter continuum and line emission at 350GHz. The observed frequency range covers tracers of dense gas (e.g., H^13^CO^+^, C^17^O), molecular outflows (e.g., SiO), and hot cores (e.g., CH_3_CN, CH_3_OH). These observations were complemented with infrared and centimeter data.
- ID:
- ivo://CDS.VizieR/J/A+A/593/A49
- Title:
- G35.20-0.74N VLA continuum images
- Short Name:
- J/A+A/593/A49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Atacama Large Millimeter/submillimeter Array (ALMA) observations of the high-mass star-forming region G35.20-0.74N have revealed the presence of a Keplerian disk in core B rotating about a massive object of 18M_{sun}_, as computed from the velocity field. The luminosity of such a massive star would be comparable to (or higher than) the luminosity of the whole star-forming region. To solve this problem it has been proposed that core B could harbor a binary system. This could also explain the possible precession of the radio jet associated with this core, which has been suggested by its S-shaped morphology. We establish the origin of the free-free emission from core B and investigate the existence of a binary system at the center of this massive core and the possible precession of the radio jet. We carried out VLA continuum observations of G35.20-0.74N at 2cm in the B configuration and at 1.3cm and 7mm in the A and B configurations. The bandwidth at 7mm covers the CH3OH maser line at 44.069GHz. Continuum images at 6 and 3.6cm in the A configuration were obtained from the VLA archive. We also carried out VERA observations of the H_2_O maser line at 22.235GHz.
- ID:
- ivo://CDS.VizieR/J/ApJS/229/25
- Title:
- GOALS sample PACS and SPIRE fluxes
- Short Name:
- J/ApJS/229/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Far-infrared images and photometry are presented for 201 Luminous and Ultraluminous Infrared Galaxies [LIRGs: log(L_IR_/L_{sun}_)=11.00-11.99, ULIRGs: log(L_IR_/L_{sun}_)=12.00-12.99], in the Great Observatories All-Sky LIRG Survey (GOALS), based on observations with the Herschel Space Observatory Photodetector Array Camera and Spectrometer (PACS) and the Spectral and Photometric Imaging Receiver (SPIRE) instruments. The image atlas displays each GOALS target in the three PACS bands (70, 100, and 160{mu}m) and the three SPIRE bands (250, 350, and 500{mu}m), optimized to reveal structures at both high and low surface brightness levels, with images scaled to simplify comparison of structures in the same physical areas of ~100x100kpc^2^. Flux densities of companion galaxies in merging systems are provided where possible, depending on their angular separation and the spatial resolution in each passband, along with integrated system fluxes (sum of components). This data set constitutes the imaging and photometric component of the GOALS Herschel OT1 observing program, and is complementary to atlases presented for the Hubble Space Telescope, Spitzer Space Telescope, and Chandra X-ray Observatory. Collectively, these data will enable a wide range of detailed studies of active galactic nucleus and starburst activity within the most luminous infrared galaxies in the local universe.
- ID:
- ivo://CDS.VizieR/J/ApJ/715/572
- Title:
- GOALS UV and FIR properties
- Short Name:
- J/ApJ/715/572
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Great Observatories All-sky LIRG Survey (GOALS) consists of a complete sample of 202 luminous infrared galaxies (LIRGs) selected from the IRAS Revised Bright Galaxy Sample (RBGS; Sanders et al. 2003, Cat. J/AJ/126/1607). The galaxies span the full range of interaction stages, from isolated galaxies to interacting pairs to late stage mergers. We present a comparison of the UV and infrared properties of 135 galaxies in GOALS observed by GALEX and Spitzer. For interacting galaxies with separations greater than the resolution of GALEX and Spitzer (~2"-6"), we assess the UV and IR properties of each galaxy individually. The contribution of the FUV to the measured star formation rate (SFR) ranges from 0.2% to 17.9%, with a median of 2.8% and a mean of 4.0+/-0.4%. The specific star formation rate (SSFR) of the GOALS sample is extremely high, with a median value (3.9x10^-10^/yr) that is comparable to the highest SSFRs seen in the Spitzer Infrared Nearby Galaxies Survey sample. We examine the position of each galaxy on the IR excess-UV slope (IRX-{beta}) diagram as a function of galaxy properties, including IR luminosity and interaction stage.
- ID:
- ivo://CDS.VizieR/J/ApJ/859/33
- Title:
- GOBELINS. IV. VLBA obs. of Taurus
- Short Name:
- J/ApJ/859/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new trigonometric parallaxes and proper motions of young stellar objects in the Taurus molecular cloud complex from observations collected with the Very Long Baseline Array as part of the Gould's Belt Distances Survey. We detected 26 young stellar objects and derived trigonometric parallaxes for 18 stars with an accuracy of 0.3% to a few percent. We modeled the orbits of six binaries and determined the dynamical masses of the individual components in four of these systems (V1023 Tau, T Tau S, V807 Tau, and V1000 Tau). Our results are consistent with the first trigonometric parallaxes delivered by the Gaia satellite and reveal the existence of significant depth effects. We find that the central portion of the dark cloud Lynds 1495 is located at d=129.5+/-0.3pc, while the B216 clump in the filamentary structure connected to it is at d=158.1+/-1.2pc. The closest and remotest stars in our sample are located at d=126.6+/-1.7pc and d=162.7+/-0.8pc, yielding a distance difference of about 36pc. We also provide a new distance estimate for HL Tau that was recently imaged. Finally, we compute the spatial velocity of the stars with published radial velocity and investigate the kinematic properties of the various clouds and gas structures in this region.
- ID:
- ivo://CDS.VizieR/J/ApJ/865/73
- Title:
- GOBELINS. V. Kinematics of Perseus
- Short Name:
- J/ApJ/865/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive the distance and structure of the Perseus molecular cloud by combining trigonometric parallaxes from Very Long Baseline Array (VLBA) observations, taken as part of the GOBELINS survey and Gaia Data Release 2. Based on our VLBA astrometry, we obtain a distance of 321+/-10pc for IC 348. This is fully consistent with the mean distance of 320+/-26 measured by Gaia. The VLBA observations toward NGC 1333 are insufficient to claim a successful distance measurement to this cluster. Gaia parallaxes, on the other hand, yield a mean distance of 293+/-22pc. Hence, the distance along the line of sight between the eastern and western edges of the cloud is ~30pc, which is significantly smaller than previously inferred. We use Gaia proper motions and published radial velocities to derive the spatial velocities of a selected sample of stars. The average velocity vectors with respect to the LSR are (u,v,w)=(-6.1+/-1.6, 6.8+/-1.1, -0.9+/-1.2) and (-6.4+/-1.0, 2.1+/-1.4, -2.4+/-1.0)km/s for IC 348 and NGC 1333, respectively. Finally, our analysis of the kinematics of the stars has shown that there is no clear evidence of expansion, contraction, or rotational motions within the clusters.
- ID:
- ivo://archive.stsci.edu/hst/ghrs
- Title:
- Goddard High Resolution Spectrograph
- Short Name:
- HST.GHRS
- Date:
- 23 Jul 2020 19:49:16
- Publisher:
- Space Telescope Science Institute Archive
- Description:
- GHRS was used to make finely detailed spectroscopic observations of ultraviolet sources, but was removed from HST in February 1997.