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571. General Catalogue of 6.7GHz Methanol Masers
ID:
ivo://CDS.VizieR/J/A+A/432/737
Title:
General Catalogue of 6.7GHz Methanol Masers
Short Name:
J/A+A/432/737
Date:
21 Oct 2021
Publisher:
CDS
Description:
Methanol masers are often detected in regions of intense star formation. Several studies in the last decade indicate that they may even be the earliest signpost of a high-mass star-forming region. Their powerful emission makes them very good candidates for observations using both single-dish telescopes and interferometers, the latter allows detailed structural and dynamical study of these objects. We present here a catalogue of all known 6.7GHz methanol masers, discovered both by surveys that targeted possible associated objects and unbiased surveys covering a large fraction of galactic longitudes across the Galactic plane 0.5{deg}<=b<=0.5deg} for most of the regions). The 519 sources which are listed with their kinematic (galactocentric and heliocentric) distance as well as possibly associated IR objects. We find that 6.7GHz methanol masers clearly trace the molecular ring of our Galaxy, where most of the OB associations are located. The present list of masers also reports detections of other masing transitions of methanol as further information for the study of the maser phenomenon. In a further publication we will address some statistical considerations.
572. Geometry of radio pulsar magnetospheres
ID:
ivo://CDS.VizieR/J/AZh/88/954
Title:
Geometry of radio pulsar magnetospheres
Short Name:
J/AZh/88/954
Date:
21 Oct 2021
Publisher:
CDS
Description:
Data on the profiles and polarization of the 10- and 20-cm emission of radio pulsars are used to calculate the angle {beta} between the rotational axis of the neutron star and its magnetic moment. It is shown that, for these calculations, it is sufficient to use catalog values of the pulse width at the 10% level W10, since the broadening of the observed pulses due to the transition to the full width W0 and narrowing of the pulses associated with the emission of radiation along tangents to the field lines approximately cancel each other out. The angles {beta}1 are calculated for 283 pulsars at 20cm and 132 pulsars at 10cm, assuming that the line of sight passes through the center of the emission cone.
573. GG Tau A ALMA ^13^CO and C^18^O(3-2) maps
ID:
ivo://CDS.VizieR/J/A+A/635/A12
Title:
GG Tau A ALMA ^13^CO and C^18^O(3-2) maps
Short Name:
J/A+A/635/A12
Date:
21 Oct 2021
Publisher:
CDS
Description:
GG Tau A is the prototype of a young triple T Tauri star that is surrounded by a massive and extended Keplerian outer disk. The central cavity is not devoid of gas and dust and at least GG Tau Aa exhibits its own disk of gas and dust emitting at millimeter wavelengths. Its observed properties make this source an ideal laboratory for investigating planet formation in young multiple solartype stars. We used new ALMA ^13^CO and C^18^O(3-2) observations obtained at high angular resolution (~0.2") together with previous CO(3-2) and (6-5) ALMA data and continuum maps at 1.3 and 0.8mm in order to determine the gas properties (temperature, density, and kinematics) in the cavity and to a lesser extent in the outer disk. By deprojecting, we studied the radial and azimuthal gas distribution and its kinematics. We also applied a new method to improve the deconvolution of the CO data and in particular better quantify the emission from gas inside the cavity. We perform local nonlocal thermodynamic equilibrium studies in order to determine the excitation conditions and relevant physical parameters inside the ring and in the central cavity. Residual emission after removing a smooth-disk model indicates unresolved structures at our angular resolution, probably in the form of irregular rings or spirals. The outer disk is cold, with a temperature <20K beyond 250au that drops quickly ({prop.to}r^-1^). The kinematics of the gas inside the cavity reveals infall motions at about 10% of the Keplerian speed. We derive the amount of gas in the cavity, and find that the brightest clumps, which contain about 10% of this mass, have kinetic temperatures 40-80K, CO column densities of a few 10^17^cm^-2^, and H_2_ densities around 10^7^cm^-3^. Although the gas in the cavity is only a small fraction of the disk mass, the mass accretion rate throughout the cavity is comparable to or higher than the stellar accretion rate. It is accordingly sufficient to sustain the circumstellar disks on a long timescale.
574. 148GHz ACT extragalactic sources catalog
ID:
ivo://CDS.VizieR/J/ApJ/731/100
Title:
148GHz ACT extragalactic sources catalog
Short Name:
J/ApJ/731/100
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on extragalactic sources detected in a 455deg^2^ map of the southern sky made with data at a frequency of 148GHz from the Atacama Cosmology Telescope (ACT) 2008 observing season. We provide a catalog of 157 sources with flux densities spanning two orders of magnitude: from 15mJy to 1500mJy. Comparison to other catalogs shows that 98% of the ACT detections correspond to sources detected at lower radio frequencies. Three of the sources appear to be associated with the brightest cluster galaxies of low-redshift X-ray-selected galaxy clusters. Estimates of the radio to millimeter-wave spectral indices and differential counts of the sources further bolster the hypothesis that they are nearly all radio sources, and that their emission is not dominated by re-emission from warm dust. In a bright (>50mJy) 148GHz selected sample with complete cross-identifications from the Australia Telescope 20GHz survey, we observe an average steepening of the spectra between 5, 20, and 148GHz with median spectral indices of {alpha}_5-20_=-0.07+/-0.06, {alpha}_20-148_=-0.39+/-0.04, and {alpha}_5-148_=-0.20+/-0.03. When the measured spectral indices are taken into account, the 148GHz differential source counts are consistent with previous measurements at 30GHz in the context of a source count model dominated by radio sources. Extrapolating with an appropriately rescaled model for the radio source counts, the Poisson contribution to the spatial power spectrum from synchrotron-dominated sources with flux density less than 20mJy is C^Sync^=(2.8+/-0.3)x10^-6^{mu}K^2^.
575. 15GHz and jet properties of MOJAVE blazars
ID:
ivo://CDS.VizieR/J/ApJ/742/27
Title:
15GHz and jet properties of MOJAVE blazars
Short Name:
J/ApJ/742/27
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate the Fermi Large Area Telescope {gamma}-ray and 15GHz Very Long Baseline Array radio properties of a joint {gamma}-ray and radio-selected sample of active galactic nuclei (AGNs) obtained during the first 11 months of the Fermi mission (2008 August 4-2009 July 5). Our sample contains the brightest 173 AGNs in these bands above declination -30{deg} during this period, and thus probes the full range of {gamma}-ray loudness ({gamma}-ray to radio band luminosity ratio) in the bright blazar population. The latter quantity spans at least 4 orders of magnitude, reflecting a wide range of spectral energy distribution (SED) parameters in the bright blazar population. The BL Lac objects, however, display a linear correlation of increasing {gamma}-ray loudness with synchrotron SED peak frequency, suggesting a universal SED shape for objects of this class.
576. 1.4GHz and X-ray sources in 12 clusters of galaxies
ID:
ivo://CDS.VizieR/J/ApJ/740/59
Title:
1.4GHz and X-ray sources in 12 clusters of galaxies
Short Name:
J/ApJ/740/59
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using Chandra imaging spectroscopy and Very Large Array (VLA) L-band radio maps, we have identified radio sources at P_1.4GHz_>=5x10^23^W/Hz and X-ray point sources (XPSs) at L_0.3-8keV_>=5x10^42^erg/s in L>L* galaxies in 12 high-redshift (0.4<z<1.2) clusters of galaxies. The radio galaxies and XPSs in this cluster sample, chosen to be consistent with Coma Cluster progenitors at these redshifts, are compared to those found at low-z analyzed in Hart et al. (Paper I, 2009ApJ...705..854H). Within a projected radius of 1Mpc of the cluster cores, we find 17 cluster radio galaxies (11 with secure redshifts, including one luminous FR II radio source at z=0.826, and six more with host galaxy colors similar to cluster ellipticals). Within this same projected radius, we identify seven spectroscopically confirmed cluster XPSs, all with cluster red-sequence (CRS) host galaxy colors. Consistent with the results from Martini et al. (2009ApJ...701...66M), we estimate a minimum X-ray active fraction of 1.4%+/-0.8% for cluster red-sequence galaxies in high-z clusters, corresponding to an approximate 10-fold increase from 0.15%+/-0.15% at low-z. Although complete redshift information is lacking for several XPSs in z>0.4 cluster fields, the increased numbers and luminosities of the CRS radio galaxies and XPSs suggest a substantial (9-10-fold) increase in the heat injected into high-redshift clusters by AGNs compared to the present epoch.
577. 1.49 GHz atlas of the IRAS bright galaxies
ID:
ivo://CDS.VizieR/J/ApJS/73/359
Title:
1.49 GHz atlas of the IRAS bright galaxies
Short Name:
J/ApJS/73/359
Date:
21 Oct 2021
Publisher:
CDS
Description:
This catalog contains 1.49 GHz VLA observations of sources from the IRAS Bright Galaxy Sample. The original IRAS Bright Galaxy Sample (Soifer et al., 1987ApJ...320..238S) comprises 324 extragalactic objects with 60 micron flux densities above 5.4 Jy. It is the infrared analog of the radio 3CR or optical Shapley-Ames samples. Recalibration of the IRAS flux densities led to a revised Bright Galaxy Sample (Soifer et al., 1989AJ.....98..766S) containing 313 sources stronger than 5.24 Jy at 60 microns. Only one source from these samples was not detected (NGC1377) at 1.49 GHz. For most sources, multiple observations were conducted with different synthesized beam areas. Thus, for a given galaxy there may be several rows in the table reporting data at different angular resolution or reporting different radio components of the object. A low-resolution observation was used to yield an accurate total flux density and a high-resolution observation was used to resolve the brightest components clearly. These observations were originally presented in Condon, et al., (1990ApJS...73..359C).
578. 6.7GHz CH_3_OH maser in G24.78+0.08
ID:
ivo://CDS.VizieR/J/A+A/616/A66
Title:
6.7GHz CH_3_OH maser in G24.78+0.08
Short Name:
J/A+A/616/A66
Date:
21 Oct 2021
Publisher:
CDS
Description:
G24.78+0.08 is a well known high-mass star-forming region, where several molecular cores harboring OB young stellar objects are found inside a clump of size ~=1pc. This article focuses on the most prominent of these cores, A1, where an intense hypercompact (HC) HII region has been discovered by previous observations. Our aim is to determine the physical conditions and the kinematics of core A1, and study the interaction of the HII region with the parental molecular core. We combine ALMA 1.4mm high-angular resolution (~=0.2'') observations of continuum and line emission with multi-epoch Very Long Baseline Interferometry data of water 22GHz and methanol 6.7GHz masers. These observations allow us to study the gas kinematics on linear scales from 10 to 10^4^au, and to accurately map the physical conditions of the gas over core A1. The 1.4mm continuum is dominated by free-free emission from the intense HC HII region (size~=1000au) observed to the North of core A1 (region A1N). Analyzing the H30{alpha} line, we reveal a fast bipolar flow in the ionized gas, covering a range of LSR velocities (VLSR) of ~=60km/s. The amplitude of the VLSR gradient, 22km/s/mpc, is one of the highest so far observed towards HC HII regions. Water and methanol masers are distributed around the HC HII region in A1N, and the maser three-dimensional (3D) velocities clearly indicate that the ionized gas is expanding at high speed (>=200km/s) into the surrounding molecular gas. The temperature distribution (in the range 100-400K) over core A1, traced with molecular (CH_3_OCHO, ^13^CH_3_CN, ^13^CH_3_OH, and CH_3_CH_2_CN) transitions with level energy in the range 30K<=E_u_/k<=300K, reflects the distribution of shocks produced by the fast-expansion of the ionized gas of the HII region. The high-energy (550K<=E_u_/k<=800K) transitions of vibrationally excited CH_3_CN are likely radiatively pumped, and their rotational temperature can significantly differ from the kinetic temperature of the gas. Over core A1, the VLSR maps from both the 1.4mm molecular lines and the 6.7GHz methanol masers consistently show a VLSR gradient (amplitude ~=0.3km/s/mpc) directed approximately S-N. Rather than gravitationally supported rotation of a massive toroid, we interpret this velocity gradient as a relatively slow expansion of core A1.
579. 6.7GHz Class II methanol maser survey
ID:
ivo://CDS.VizieR/J/ApJ/846/160
Title:
6.7GHz Class II methanol maser survey
Short Name:
J/ApJ/846/160
Date:
21 Oct 2021
Publisher:
CDS
Description:
We performed a systematic 6.7GHz Class II methanol maser survey using the Shanghai Tianma Radio Telescope toward targets selected from the all-sky Wide-Field Infrared Survey Explorer (WISE) point catalog. In this paper, we report the results from the survey of those at high Galactic latitudes, i.e., |b|>2{deg}. Of 1473 selected WISE point sources at high latitude, 17 point positions that were actually associated with 12 sources were detected with maser emission, reflecting the rarity (1%-2%) of methanol masers in the region away from the Galactic plane. Out of the 12 sources, 3 are detected for the first time. The spectral energy distribution at infrared bands shows that these new detected masers occur in the massive star-forming regions. Compared to previous detections, the methanol maser changes significantly in both spectral profiles and flux densities. The infrared WISE images show that almost all of these masers are located in the positions of the bright WISE point sources. Compared to the methanol masers at the Galactic plane, these high-latitude methanol masers provide good tracers for investigating the physics and kinematics around massive young stellar objects, because they are believed to be less affected by the surrounding cluster environment.
580. 95GHz class I methanol maser survey
ID:
ivo://CDS.VizieR/J/ApJS/200/5
Title:
95GHz class I methanol maser survey
Short Name:
J/ApJS/200/5
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report a survey with the Purple Mountain Observatory 13.7m radio telescope for class I methanol masers from the 95GHz (8_0_-7_1_A^+^) transition. Two hundred and fourteen target sources were selected by combining information from both the Spitzer GLIMPSE and 1.1mm Bolocam Galactic Plane Survey (BGPS) catalogs. The observed sources satisfy the GLIMPSE mid-IR criteria of [3.6]-[4.5]>1.3, [3.6]-[5.8]>2.5, [3.6]-[8.0]>2.5 and 8.0um mag less than 10; they also have an associated 1.1mm BGPS source. Class I methanol maser emission was detected in 63 sources, corresponding to a detection rate of 29% for this survey. For the majority of detections (43), this is the first identification of class I methanol masers associated with these sources. We show that the intensity of the class I methanol maser emission is not closely related to mid-IR intensity or the colors of the GLIMPSE point sources; however, it is closely correlated with properties (mass and beam-averaged column density) of the BGPS sources. Comparison of measures of star formation activity for the BGPS sources with and without class I methanol masers indicates that the sources with class I methanol masers usually have higher column density and larger flux density than those without them.