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951. M 2-9 ^12^CO and ^13^CO channel maps
ID:
ivo://CDS.VizieR/J/A+A/600/A4
Title:
M 2-9 ^12^CO and ^13^CO channel maps
Short Name:
J/A+A/600/A4
Date:
21 Oct 2021
Publisher:
CDS
Description:
M 2-9 is a young planetary nebula (PN) that shows the characteristics of its last ejections in unprecedented detail. These last ejections are thought to trigger the post-asymptotic giant branch evolution. To assemble an overall picture of how M 2-9 was shaped, we analyzed the characteristics of the different molecular gas components and their relation with the warmer parts of the nebula that are visible in the optical domain. ^12^CO and ^13^CO J=3-2 line emission maps were obtained with the Atacama Large Millimeter/submillimeter Array with high angular-resolution and sensitivity.
952. Medicina 6.7GHz methanol masers survey
ID:
ivo://CDS.VizieR/J/A+AS/134/115
Title:
Medicina 6.7GHz methanol masers survey
Short Name:
J/A+AS/134/115
Date:
21 Oct 2021
Publisher:
CDS
Description:
File table2 contains the name of the sources and their coordinates (1950) observed, but not detected, with the Medicina Radiotelescope at 6.7GHz in 1995, March. Source are associated with one or more type of phenomena typical of star forming regions (see note 1 for code description). The number of non detected sources is 387.
953. Megamaser Cosmology Project. VIII. NGC5765B
ID:
ivo://CDS.VizieR/J/ApJ/817/128
Title:
Megamaser Cosmology Project. VIII. NGC5765B
Short Name:
J/ApJ/817/128
Date:
21 Oct 2021
Publisher:
CDS
Description:
As part of the Megamaser Cosmology Project, here we present a new geometric distance measurement to the megamaser galaxy NGC 5765b. Through a series of very long baseline interferometry observations, we have confirmed the water masers trace a thin, sub-parsec Keplerian disk around the nucleus, implying an enclosed mass of 4.55+/-0.40x10^7^M_{sun}_. Meanwhile, from single-dish monitoring of the maser spectra over two years, we measured the secular drifts of maser features near the systemic velocity of the galaxy with rates between 0.5 and 1.2km/s/yr. Fitting a warped, thin-disk model to these measurements, we determine a Hubble Constant H_0_ of 66.0+/-6.0km/s/Mpc with an angular-diameter distance to NGC 5765b of 126.3+/-11.6Mpc. Apart from the distance measurement, we also investigate some physical properties related to the maser disk in NGC 5765b. The high-velocity features are spatially distributed into several clumps, which may indicate the existence of a spiral density wave associated with the accretion disk. For the redshifted features, the envelope defined by the peak maser intensities increases with radius. The profile of the systemic masers in NGC 5765b is smooth and shows almost no structural changes over the two years of monitoring time, which differs from the more variable case of NGC 4258.
954. Megamaser Cosmology Project. XI. Z74-64 VLBI obs.
ID:
ivo://CDS.VizieR/J/ApJ/890/118
Title:
Megamaser Cosmology Project. XI. Z74-64 VLBI obs.
Short Name:
J/ApJ/890/118
Date:
21 Oct 2021
Publisher:
CDS
Description:
As part of the survey component of the Megamaser Cosmology Project, we have discovered a disk megamaser system in the galaxy CGCG 074-064. Using the Green Bank Telescope and the Very Large Array, we have obtained spectral monitoring observations of this maser system at a monthly cadence over the course of two years. We find that the systemic maser features display line-of-sight accelerations of ~4.4km/s/yr that are nearly constant with velocity, while the high-velocity maser features show accelerations that are consistent with zero. We have also used the High-Sensitivity Array to make a high-sensitivity very long baseline interferometric map of the maser system in CGCG 074-064, which reveals that the masers reside in a thin, edge-on disk with a diameter of ~1.5mas (0.6pc). Fitting a three-dimensional warped disk model to the data, we measure a black hole mass of 2.42_-0.20_^+0.22^x10^7^M_{sun}_ and a geometric distance to the system of 87.6_-7.2_^+7.9^Mpc. Assuming a cosmic microwave background-frame recession velocity of 7308+/-150km/s, we constrain the Hubble constant to H_0_=81.0_-6.9_^+7.4^(stat.)+/-1.4(sys.)km/s/Mpc.
955. Megamaser detection in Seyfert galaxies
ID:
ivo://CDS.VizieR/J/A+A/530/A147
Title:
Megamaser detection in Seyfert galaxies
Short Name:
J/A+A/530/A147
Date:
21 Oct 2021
Publisher:
CDS
Description:
We revisit the relation between H_2_O maser detection rate and nuclear obscuration for a sample of 114 Seyfert galaxies, drawn from the CfA, 12um and IRAS F25/F60 catalogs. These sources have mid-infrared spectra from the Spitzer Space Telescope and they are searched for X-ray and [OIII] (5007{AA}) fluxes from the literature. We use the strength of the [OIV] (25.9um) emission line as tracer for the intrinsic AGN strength. After normalization by [OIV] the observed X-ray flux provides information about X-ray absorption. The distribution of X-ray/[OIV] flux ratios is significantly different for masers and non-masers: The maser detected Seyfert-2s (Sy 1.8-2.0) populate a distinct X-ray/[OIV] range which is, on average, about a factor four lower than the range of Seyfert-2 non-masers and about a factor of ten lower than the range of Seyfert-1s (Sy 1.0-1.5). Non-masers are almost equally distributed over the entire X-ray/[OIV] range. This provides evidence that high nuclear obscuration plays a crucial role for the probability of maser detection. Furthermore, after normalization with [OIV], we find a similar but weaker trend for the distribution of the maser detection rate with the absorption of the 7um dust continuum. This suggests that the obscuration of the 7um continuum occurs on larger spatial scales than that of the X-rays. Hence, in the AGN unified model, at moderate deviation from edge-on, the 7um dust absorption may occur without proportionate X-ray absorption. The absorption of [OIII] appears unrelated to maser detections. The failure to detect masers in obscured AGN is most likely due to insufficient observational sensitivity.
956. Merging galaxy cluster deep observations
ID:
ivo://CDS.VizieR/J/ApJS/240/39
Title:
Merging galaxy cluster deep observations
Short Name:
J/ApJS/240/39
Date:
18 Jan 2022 14:59:05
Publisher:
CDS
Description:
Multi-band photometric and multi-object spectroscopic surveys of merging galaxy clusters allow for the characterization of the distributions of constituent DM and galaxy populations, constraints on the dynamics of the merging subclusters, and an understanding of galaxy evolution of member galaxies. We present deep photometric observations from Subaru/SuprimeCam and a catalog of 4431 spectroscopic galaxies from Keck/DEIMOS observations of 29 merging galaxy clusters ranging in redshift from z=0.07 to 0.55. The ensemble is compiled based on the presence of radio relics, which highlight cluster-scale collisionless shocks in the intracluster medium. Together with the spectroscopic and photometric information, the velocities, timescales, and geometries of the respective merging events may be tightly constrained. In this preliminary analysis, the velocity distributions of 28 of the 29 clusters are shown to be well fit by single Gaussians. This indicates that radio-relic mergers largely occur transverse to the line of sight and/or near-apocenter. In this paper, we present our optical and spectroscopic surveys, preliminary results, and a discussion of the value of radio-relic mergers for developing accurate dynamical models of each system.
957. Methanol (CH_3_OH) and OH masers in NGC 6334I
ID:
ivo://CDS.VizieR/J/ApJ/854/170
Title:
Methanol (CH_3_OH) and OH masers in NGC 6334I
Short Name:
J/ApJ/854/170
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the first sub-arcsecond VLA imaging of 6GHz continuum, methanol maser, and excited-state hydroxyl maser emission toward the massive protostellar cluster NGC 6334I following the recent 2015 outburst in (sub)millimeter continuum toward MM1, the strongest (sub)millimeter source in the protocluster. In addition to detections toward the previously known 6.7GHz Class II methanol maser sites in the hot core MM2 and the UCHII region MM3 (NGC 6334F), we find new maser features toward several components of MM1, along with weaker features ~1" north, west, and southwest of MM1, and toward the nonthermal radio continuum source CM2. None of these areas have heretofore exhibited Class II methanol maser emission in three decades of observations. The strongest MM1 masers trace a dust cavity, while no masers are seen toward the strongest dust sources MM1A, 1B, and 1D. The locations of the masers are consistent with a combination of increased radiative pumping due to elevated dust grain temperature following the outburst, the presence of infrared photon propagation cavities, and the presence of high methanol column densities as indicated by ALMA images of thermal transitions. The nonthermal radio emission source CM2 (2" north of MM1) also exhibits new maser emission from the excited 6.035 and 6.030GHz OH lines. Using the Zeeman effect, we measure a line-of-sight magnetic field of +0.5 to +3.7mG toward CM2. In agreement with previous studies, we also detect numerous methanol and excited OH maser spots toward the UCHII region MM3, with predominantly negative line-of-sight magnetic field strengths of -2 to -5mG and an intriguing south-north field reversal.
958. Methanol emission from the Galactic Center
ID:
ivo://CDS.VizieR/J/ApJ/764/L19
Title:
Methanol emission from the Galactic Center
Short Name:
J/ApJ/764/L19
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the discovery of a widespread population of collisionally excited methanol J=4_-1_ to 3_0_E sources at 36.2GHz from the inner 66'x18' (160x43pc) of the Galactic center. This spectral feature was imaged with a spectral resolution of 16.6km/s taken from 41 channels of a Very Large Array continuum survey of the Galactic center region. The revelation of 356 methanol sources, most of which are maser candidates, suggests a large abundance of methanol in the gas phase in the Galactic center region. There is also spatial and kinematic correlation between SiO (2-1) and CH_3_OH emission from four Galactic center clouds: the +50 and +20km/s clouds and G0.13-0.13 and G0.25+0.01. The enhanced abundance of methanol is accounted for in terms of induced photodesorption by cosmic rays as they travel through a molecular core, collide, dissociate, ionize, and excite Lyman Werner transitions of H_2_. A time-dependent chemical model in which cosmic rays drive the chemistry of the gas predicts CH_3_OH abundance of 10^-8^ to 10^-7^ on a chemical timescale of 5x10^4^ to 5x10^5^ years. The average methanol abundance produced by the release of methanol from grain surfaces is consistent with the available data.
959. Methanol emission of isolated maser condensations
ID:
ivo://CDS.VizieR/J/AZh/84/839
Title:
Methanol emission of isolated maser condensations
Short Name:
J/AZh/84/839
Date:
21 Oct 2021
Publisher:
CDS
Description:
The distribution of the radial velocities of class I methanol masers relative to the velocities of their parent molecular clouds is analyzed. This analysis is based on catalog data for methanol masers detected up to the present time in both the northern and southern hemispheres, together with catalog data for the CS(2-1) line, which traces dense, quiescent gas. Results for a large sample of sources show that, in contrast to class II methanol masers, which undergo Keplerian motions in protoplanetary disks, class I methanol masers retain their velocities in the local system of rest of the surrounding medium, and do not participate in the ejection of matter in bipolar out flows. They can be adequately described using a model in which matter ejected from active parts of the associated star-forming regions flows around isolated maser condensations. This compresses the maser clumps, enhancing the concentration of methanol and facilitating collisional pumping of the masers.
960. Methanol maser associated outflows
ID:
ivo://CDS.VizieR/J/MNRAS/444/566
Title:
Methanol maser associated outflows
Short Name:
J/MNRAS/444/566
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have selected the positions of 54 6.7GHz methanol masers from the Methanol Multibeam Survey catalogue, covering a range of longitudes between 20{deg} and 34{deg} of the Galactic plane. These positions were mapped in the J=3-2 transition of both the ^13^CO and C^18^O lines. A total of 58 ^13^CO emission peaks are found in the vicinity of these maser positions. We search for outflows around all ^13^CO peaks, and find evidence for high-velocity gas in all cases, spatially resolving the red and blue outflow lobes in 55 cases. Of these sources, 44 have resolved kinematic distances, and are closely associated with the 6.7GHz masers, a subset referred to as Methanol Maser Associated Outflows (MMAOs). We calculate the masses of the clumps associated with each peak using 870{mu}m continuum emission from the ATLASGAL survey. A strong correlation is seen between the clump mass and both outflow mass and mechanical force, lending support to models in which accretion is strongly linked to outflow. We find that the scaling law between outflow activity and clump masses observed for low-mass objects, is also followed by the MMAOs in this study, indicating a commonality in the formation processes of low-mass and high-mass stars.