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1131. NGC 4217 radio and polarization maps
ID:
ivo://CDS.VizieR/J/A+A/639/A111
Title:
NGC 4217 radio and polarization maps
Short Name:
J/A+A/639/A111
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate the radio continuum halo, the magnetic field, and the transport processes of the CRs of the edge-on spiral galaxy NGC 4217 using Continuum HAlos in Nearby Galaxies - an Evla Survey (CHANG-ES) radio data at two frequencies, 6GHz (C-band) and 1.5GHz (L-band), and supplemental LOFAR data of this galaxy at 150MHz. With additional X-ray Chandra data, we study the connection of radio features to the diffuse hot gas around NGC 4217. NGC 4217 shows a large-scale X-shaped magnetic field structure, covering a major part of the galaxy with a mean total magnetic field strength in the disk of 9G. From the analysis of the rotation measure map at C-band, we found that the direction of the disk magnetic field is pointing inward. A helical outflow structure is furthermore present in the northwestern part of the galaxy, which is extended nearly 7 kpc into the halo. More polarized emission is observed on the approaching side of the galaxy, indicating that Faraday depolarization has to be considered at C-band. With a simplified galaxy disk model, we are able to explain the finding of higher polarized intensity on the approaching side. We generalize the model to predict that roughly 75% of edge-on spiral galaxies will show higher polarized intensity on the approaching side. Many loop and shell structures are found throughout the galaxy in total intensity at C-band. One structure, a symmetric off-center (to the southwest of the disk) superbubble-like structure is prominent in total and polarized intensity, as well as in Halpha and optical dust filaments. This is at a location where a second peak of total intensity (to the southwest of the disk) is observed, making this superbubble-like structure a possible result of a concentrated star formation region in the disk. The X-ray diffuse emission shows similarities to the polarized diffuse emission of NGC 4217. The flux density extension of the radio continuum halo increases toward lower frequencies. While the total flux density of the disk and halo are comparable at C-band, the contribution of the disk flux density decreases toward LOFAR to 18% of the total flux density. Dumbbell-shaped structures are present at C-band and at the LOFAR frequency. Total intensity profiles at the two CHANG-ES bands and the LOFAR frequency show a clear two-component behavior and were fit best with a two-component exponential fit. The halo scale heights are 1.10+/-0.04kpc, 1.43+/-0.09kpc, and 1.55+/-0.04kpc in C-band, L-band, and 150MHz, respectively. The frequency dependence of these scale heights between C-band and L-band suggests advection to be the main transport process. The 1D CRE transport modeling shows that advection appears to be more important than diffusion.
1132. NGC 4631 total intensity images
ID:
ivo://CDS.VizieR/J/A+A/632/A10
Title:
NGC 4631 total intensity images
Short Name:
J/A+A/632/A10
Date:
21 Oct 2021
Publisher:
CDS
Description:
NGC 4631 is an interacting galaxy that exhibits one of the largest, gaseous halos observed among edge-on galaxies. We aim to examine the synchrotron and cosmic-ray propagation properties of its disk and halo emission with new radio continuum data. Radio continuum observations of NGC 4631 were performed with the Karl G. Jansky Very Large Array at C-band (5.99GHz) in the C and D array configurations, and at L-band (1.57GHz) in the B, C, and D array configurations. Complementary observations of NGC 4631 with the Effelsberg telescope were performed at 1.42 and 4.85 GHz. The interferometric total intensity data were combined with the single-dish Effelsberg data in order to recover the missing large-scale total power emission. The thermal and nonthermal components of the total radio emission were separated by estimating the thermal contribution through the extinction-corrected H{alpha} emission. The H{alpha} radiation was corrected for extinction using a linear combination of the observed H{alpha} and 24{mu}m data. NGC 4631 has a global thermal fraction at 5.99(1.57)GHz of 14+/-3% (5.4+/-1.1%). The mean scale heights of the total emission in the radio halo (thick disk) at 5.99(1.57)GHz are 1.79+/-0.54kpc (1.75+/-0.27kpc) and have about the same values for the synchrotron emission. The total magnetic field of NGC 4631 has a mean strength of <Beq>~=9{mu}G in the disk, and a mean strength of <Beq>~=7{mu}G in the halo. We also studied a double-lobed background radio galaxy southwest of NGC 4631, which is an FR II radio galaxy according to the distribution of spectral index across the lobes. From the halo scale heights we estimated that the radio halo is escape-dominated with convective cosmic ray propagation, and conclude that there is a galactic wind in the halo of NGC 4631.
1133. NGC 2683 VLA C and D datacubes
ID:
ivo://CDS.VizieR/J/A+A/586/A98
Title:
NGC 2683 VLA C and D datacubes
Short Name:
J/A+A/586/A98
Date:
21 Oct 2021
Publisher:
CDS
Description:
New deep VLA D array HI observations of the highly inclined nearby spiral galaxy NGC 2683 are presented. Archival C array data were processed and added to the new observations. To investigate the 3D structure of the atomic gas disk, we made different 3D models for which we produced model HI data cubes. The main ingredients of our best-fit model are (i) a thin disk inclined by 80{deg}; (ii) a crude approximation of a spiral and/or bar structure by an elliptical surface density distribution of the gas disk; (iii) a slight warp in inclination between 10kpc<=R<=20kpc (decreasing by 10{deg}); (iv) an exponential flare that rises from 0.5kpc at R=9kpc to 4kpc at R=15kpc, stays constant until R=22kpc, and decreases its height for R>22kpc; and (v) a low surface-density gas ring with a vertical offset of 1.3kpc. The slope of NGC 2683's flare is comparable, but somewhat steeper than those of other spiral galaxies. NGC 2683's maximum height of the flare is also comparable to those of other galaxies. On the other hand, a saturation of the flare is only observed in NGC 2683. Based on the comparison between the high resolution model and observations, we exclude the existence of an extended atomic gas halo around the optical and thin gas disk. Under the assumption of vertical hydrostatic equilibrium we derive the vertical velocity dispersion of the gas. The high turbulent velocity dispersion in the flare can be explained by energy injection by (i) supernovae; (ii) magneto-rotational instabilities; (iii) interstellar medium stirring by dark matter substructure; or (iv) external gas accretion. The existence of the complex large-scale warping and asymmetries favors external gas accretion as one of the major energy sources that drives turbulence in the outer gas disk. We propose a scenario where this external accretion leads to turbulent adiabatic compression that enhances the turbulent velocity dispersion and might quench star formation in the outer gas disk of NGC 2683.
1134. NGC 2071 water masers
ID:
ivo://CDS.VizieR/J/ApJ/581/325
Title:
NGC 2071 water masers
Short Name:
J/ApJ/581/325
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have mapped the water maser emission associated with the infrared centers IRS 1 and IRS 3 of the NGC 2071 IR star-forming region at four epochs over ~4 months with the Very Long Baseline Array. We detected 269 maser features with ~1km/s line widths and measured 30 proper motions. In each infrared center, the water maser emission appears to trace parts of a protostellar disk and collimated outflow.
1135. NH3 line profiles in star-forming regions
ID:
ivo://CDS.VizieR/J/ApJ/806/74
Title:
NH3 line profiles in star-forming regions
Short Name:
J/ApJ/806/74
Date:
21 Oct 2021
Publisher:
CDS
Description:
Anomalous ammonia (NH_3_) spectra, exhibiting asymmetric hyperfine satellite intensity profiles in the (J,K)=(1,1) inversion transition, have been observed in star-forming regions for over 35 years. We present a systematic study of this "hyperfine intensity anomaly" (HIA) toward a sample of 334 high-mass star forming regions: 310 high-mass (>~100M_{sun}_) clumps and 24 infrared dark clouds. The HIA is ubiquitous in high-mass star forming regions. Although LTE excitation predicts that the intensity ratios of the outer satellites and inner satellites are exactly unity, for this sample the ensemble average ratios are 0.812+/-0.004 and 1.125+/-0.005, respectively. We have quantified the HIA and find no significant relationships between the HIA and temperature, line width, optical depth, and the stage of stellar evolution. The fact that HIAs are common in high-mass star-forming regions suggests that the conditions that lead to HIAs are ubiquitous in these regions. A possible link between HIAs and the predictions of the competitive accretion model of high-mass star formation is suggested; however, the expected trends of HIA strength with clump evolutionary stage, rotational temperature, and line width for evolving cores in competitive accretion models are not found. Thus, the exact gas structures that produce HIAs remain unknown. Turbulent gas structures are a possible explanation, but the details need to be explored.
1136. NH_3_ Odin observations towards Sgr A
ID:
ivo://CDS.VizieR/J/A+A/599/A135
Title:
NH_3_ Odin observations towards Sgr A
Short Name:
J/A+A/599/A135
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Odin satellite is now into its sixteenth year of operation, much surpassing its design life of two years. One of the sources which Odin has observed in great detail is the Sgr A Complex in the centre of the Milky Way. The aim is to study the presence of NH_3_ in the Galactic Centre and spiral arms. Recently, Odin has made complementary observations of the 572GHz NH_3_ line towards the Sgr A +50km/s cloud and Circumnuclear Disk (CND). Significant NH_3_ emission has been observed in both the +50km/s cloud and the CND. Clear NH_3_ absorption has also been detected in many of the spiral arm features along the line of sight from the Sun to the core of our Galaxy. The very large velocity width (80km/s) of the NH_3_ emission associated with the shock region in the southwestern part of the CND may suggest a formation/desorption scenario similar to that of gas-phase H_2_O in shocks/outflows.
1137. NIBLES II. Arecibo follow-up observations
ID:
ivo://CDS.VizieR/J/A+A/596/A60
Title:
NIBLES II. Arecibo follow-up observations
Short Name:
J/A+A/596/A60
Date:
21 Oct 2021
Publisher:
CDS
Description:
We obtained Arecibo HI line follow-up observations of 154 of the 2600 galaxies in the Nancay Interstellar Baryons Legacy Extragalactic Survey (NIBLES) sample. These observations are on average four times more sensitive than the original observations at the Nancay Radio Telescope. The main goal of this survey is to characterize the underlying HI properties of the NIBLES galaxies which were undetected or marginally detected at Nancay. Of the Nancay non-detections, 85% were either clearly or marginally detected at Arecibo, while 89% of the Nancay marginal detections were clearly detected. Based on the statistics of the detections relative to g-i color and r-band luminosity (Lr) distribution among our Arecibo observations, we anticipate ~60% of our 867 Nancay non-detections and marginal detections could be detected at the sensitivity of our Arecibo observations. Follow-up observations of our low luminosity (Lr<10^8.5^L_{sun}_) blue sources indicate that they have, on average, more concentrated stellar mass distributions than the Nancay detections in the same luminosity range, suggesting we may be probing galaxies with intrinsically different properties. These follow-up observations enable us to probe HI mass fractions, log(MHI/M*) 0.5dex and 1dex lower, on average, than the NIBLES and ALFALFA surveys respectively.
1138. NICMOS observations of 3CR radio sources
ID:
ivo://CDS.VizieR/J/ApJS/164/307
Title:
NICMOS observations of 3CR radio sources
Short Name:
J/ApJS/164/307
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present newly acquired images of the near-infrared counterpart of 3CR radio sources. All the sources were selected to have a redshift of less than 0.3 to allow us to obtain the highest spatial resolution. The observations were carried out as a snapshot program using the Near-Infrared Camera and Multiobject Spectrograph (NICMOS) on-board the Hubble Space Telescope (HST). In this paper we describe 69 radio galaxies observed for the first time with NICMOS during HST cycle 13. All the objects presented here are elliptical galaxies. However, each of them has unique characteristics such as close companions, dust lanes, unresolved nuclei, arclike features, globular clusters, and jets clearly visible from the images or with basic galaxy subtraction.
1139. NIKA maps of ClG J1226.9+3332 at 150 and 250GHz
ID:
ivo://CDS.VizieR/J/A+A/576/A12
Title:
NIKA maps of ClG J1226.9+3332 at 150 and 250GHz
Short Name:
J/A+A/576/A12
Date:
21 Oct 2021
Publisher:
CDS
Description:
The thermal Sunyaev-Zel'Dovich (tSZ) effect is expected to provide a low scatter mass proxy for galaxy clusters since it is directly proportional to the cluster thermal energy. The tSZ observations have proven to be a powerful tool for detecting and studying them, but high angular resolution observations are now needed to push their investigation to a higher redshift. In this paper, we report high angular (<20-arcsec) resolution tSZ observations of the high-redshift cluster CL J1226.9+3332 (z=0.89). It was imaged at 150 and 260GHz using the NIKA camera at the IRAM 30-meter telescope. The 150GHz map shows that CL J1226.9+3332 is morphologically relaxed on large scales with evidence of a disturbed core, while the 260GHz channel is used mostly to identify point source contamination. NIKA data are combined with those of Planck and X-ray from Chandra to infer the cluster's radial pressure, density, temperature, and entropy distributions. The total mass profile of the cluster is derived, and we find M_500_=5.96^+1.02^_-0.79_x10^14^M_{sun} within the radius R_500_=930^+50^_-43kpc, at a 68% confidence level. (R_500_ is the radius within which the average density is 500 times the critical density at the cluster's redshift.) NIKA is the prototype camera of NIKA2, a KIDs (kinetic inductance detectors) based instrument to be installed at the end of 2015. This work is, therefore, part of a pilot study aiming at optimizing tSZ NIKA2 large programs.
1140. NIKA Sunyaev-Zel'dovich data release
ID:
ivo://CDS.VizieR/J/A+A/614/A118
Title:
NIKA Sunyaev-Zel'dovich data release
Short Name:
J/A+A/614/A118
Date:
21 Oct 2021
Publisher:
CDS
Description:
Substructures in the hot gas atmosphere of galaxy clusters are related to their formation history and to the astrophysical processes at play in the intracluster medium (ICM). The thermal Sunyaev-Zel'dovich (tSZ) effect is directly sensitive to the line-of-sight integrated ICM pressure, and is thus particularly adapted to study ICM substructures. In this paper, we apply structure-enhancement filtering algorithms to high-resolution tSZ observations (e.g., NIKA) of distant clusters in order to search for pressure discontinuities, compressions, and secondary peaks in the ICM. The same filters are applied to toy-model images and to synthetic tSZ images extracted from RHAPSODY-G cosmological hydrodynamic simulations, in order to better interpret the extracted features. We also study the noise propagation through the filters and quantify the impact of systematic effects, such as data-processing-induced artifacts and point-source residuals, the latter being identified as the dominant potential contaminant. In three of our six NIKA-observed clusters we identify features at high signal-to-noise ratio that show clear evidence for merger events. In MACS J0717.5+3745 (z=0.55), three strong pressure gradients are observed on the east, southeast, and west sectors, and two main peaks in the pressure distribution are identified. We observe a lack of tSZ compact structure in the cool-core cluster PSZ1 G045.85+57.71 (z=0.61), and a tSZ gradient ridge dominates in the southeast. In the highest redshift cluster, CL J1226.9+3332 (z=0.89), we detect a ridge pressure gradient of ~45-arcsec (360kpc) in length associated with a secondary pressure peak in the west region. Our results show that current tSZ facilities have now reached the angular resolution and sensitivity to allow an exploration of the details of pressure substructures in clusters, even at high redshift. This opens the possibility to quantify the impact of the dynamical state on the relation between the tSZ signal and the mass of clusters, which is important when using tSZ clusters to test cosmological models. This work also marks the first NIKA cluster sample data release.