- 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.
Number of results to display per page
Search Results
- 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/A+A/655/A106
- Title:
- GO And, 84 UMa, kappa Psc ESPaDOnS spectra
- Short Name:
- J/A+A/655/A106
- Date:
- 11 Mar 2022 13:28:01
- Publisher:
- CDS
- Description:
- The aim of this work is to determine fundamental parameters of three Ap stars, GO And (HD 4778), {kappa} Psc (HD 220825), and 84 UMa (HD 120198), using spectroscopic techniques. By analysing these stars, we complete the sample of Ap stars for which fundamental parameters have additionally been derived by means of interferometry. This enables a cross-comparison of results derived by direct and indirect methods. Our study is based on the analysis of high-resolution spectra with a high signal-to-noise ratio that were obtained with ESPaDOnS spectrograph. We used an iterative method of fundamental parameter determinations that includes self-consistent modelling of the stellar atmosphere, taking individual abundances of chemical elements into account and subsequently fitting a theoretical spectral energy distribution to the observed distribution. The quality of the spectroscopic determinations was evaluated through a comparison with the interferometric results. For all investigated stars we determined fundamental parameters and derived chemical abundances that turn to be typical for Ap stars and are characterised mainly by gradual increase of heavy elements atmospheric abundance from an order of magnitude for iron peak elements up to very significant excesses of 3-4dex of the rare-earth elements relative to the solar values. The only exception is Ba which abundance is close to the solar one. There is also a significant He deficiency in the atmospheres of HD 120198 and HD 220825, whereas He abundance in HD 4778 is close to the solar one. We do not find significant Fe and Cr stratification. Using these abundances we constructed self-consistent atmospheric models for each star. The effect of the surface chemical inhomogeneity on the derived fundamental parameters did not exceed +/-100K in effective temperature which lies within a range of errors in similar self-consistent analyses of Ap stars. Finally, we compared spectroscopically derived effective temperatures, radii, and luminosity for 13 out of 14 Ap stars in benchmarking sample with the interferometric results. While radii and luminosity agree within the quoted errors of both determinations, spectroscopic effective temperatures are higher than the interferometric ones for stars with Teff>9000K. The observed hydrogen line profiles favour the spectroscopically derived temperatures.
- 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.
7509. GO Cyg BV light curves
- ID:
- ivo://CDS.VizieR/J/other/NewA/17.296
- Title:
- GO Cyg BV light curves
- Short Name:
- J/other/NewA/17.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this study, we present long term photometric variations of the close binary system GO Cyg. Modelling of the system shows that the primary is filling Roche lobe and the secondary of the system is almost filling its Roche lobe. The physical parameters of the system are M_1_=3.0+/-0.2M_{sun}_, M_2_=1.3+/-0.1M_{sun}_, R_1_=2.50+/-0.12R_{sun}_, R_2_=1.75+/-0.09R_{sun}_, L_1_=64+/-9L_{sun}_, L_2_=4.9+/-0.7L_{sun}_, and a=5.5+/-0.3R_{sun}_. Our results show that GO Cyg is the most massive system near contact binary (NCB). Analysis of times of the minima shows a sinusoidal variation with a period of 92.3+/-0.5-years due to a third body whose mass is less than 2.3M_{sun}_. Finally a period variation rate of -1.4x10^-9^d/yr has been determined using all available light curves.
- ID:
- ivo://CDS.VizieR/J/PASJ/70/S10
- Title:
- GOLDRUSH I. UV magnitudes
- Short Name:
- J/PASJ/70/S10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the UV luminosity functions (LFs) at z~4, 5, 6, and 7 based on the deep large-area optical images taken by the Hyper Suprime-Cam (HSC) Subaru Strategic Program (SSP). On the 100 deg^2^ sky of the HSC SSP data available to date, we take enormous samples consisting of a total of 579565 dropout candidates at z~4-7 by the standard color selection technique, 358 out of which are spectroscopically confirmed by our follow-up spectroscopy and other studies. We obtain UV LFs at z~4-7 that span a very wide UV luminosity range of ~0.002-100L^*^_UV_(-26<M_UV_<-14mag) by combining LFs from our program and the ultra-deep Hubble Space Telescope legacy surveys. We derive three parameters of the best-fit Schechter function, {Phi}^*^, M_UV_, and {alpha}, of the UV LFs in the magnitude range where the active galactic nucleus (AGN) contribution is negligible, and find that and {Phi}^*^ decrease from z~4 to 7 with no significant evolution of M_UV_. Because our HSC SSP data bridge the LFs of galaxies and AGNs with great statistical accuracy, we carefully investigate the bright end of the galaxy UV LFs that are estimated by the subtraction of the AGN contribution either aided by spectroscopy or the best-fit AGN UV LFs. We find that the bright end of the galaxy UV LFs cannot be explained by the Schechter function fits at >2{sigma} significance, and require either double power-law functions or modified Schechter functions that consider a magnification bias due to gravitational lensing.