- ID:
- ivo://CDS.VizieR/J/A+A/602/A31
- Title:
- G29.37+0.1 610MHz image
- Short Name:
- J/A+A/602/A31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the first detailed multiwavelength study of the radio source G29.37+0.1, which is an as-yet-unclassified object linked to the very-high-energy gamma-emitting source HESS J1844-030. The origin of the multiwavelength emission toward G29.37+0.1 has not been clarified so far, leaving open the question about the physical relationship between these sources. Using observations carried out with the Giant Metrewave Radio Telescope (GMRT), we performed high-quality full-synthesis imaging at 610MHz of the field containing G29.37+0.1. The obtained data, combined with observations at 1400MHz from the MAGPIS were used to investigate in detail the properties of its radio emission. Additionally, we reprocessed archival data obtained with the XMM-Newton and Chandra observatories in order to get a multiwavelength view of this unusual source. The radio source G29.37+0.1 mainly consists of a bright twisted structure, named the S-shaped feature. The high sensitivity of the new GMRT observations allowed the identification of potential lobes, jets and a nuclear central region in the S-shaped morphology of G29.37+0.1. We also highlight the detection of diffuse and low surface brightness emission enveloping the brightest emitting regions. The brightest emission in G29.37+0.1 has a radio synchrotron spectral index alpha=0.59+/-0.09. Variations in the spectral behaviour are observed across the whole radio source with the flattest spectral features in the central nuclear and jets components (alpha~0.3). These results lead us to conclude that the brightest radio emission from G29.37+0.1 likely represents a newly recognized radio galaxy. The identification of optical and infrared counterparts to the emission arising from the core of G29.37+0.1 strengthens our interpretation of an extragalactic origin of the radio emission. We performed several tests to explain the physical mechanism responsible for the observed X-ray emission, which appears overlapping the northeastern part of the radio emission. Our spectral analysis demonstrated that a non-thermal origin for the X-ray emission compatible with a pulsar wind nebula is quite possible. The analysis of the spatial distribution of the CO gas revealed the presence of a complex of molecular clouds located in projection adjacent to the radio halo emission and probably interacting with it. We propose that the faint halo represents a composite supernova remnant with a pulsar powered component given by the diffuse X-ray emission superimposed along the line of sight to the radio galaxy. Further broadband observations of HESS J1844-030 are needed to disentangle its origin, although its shape and position suggest an extragalactic origin connected to G29.37+0.1.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/464/3357
- Title:
- GMRT 610-MHz observations of the AMI001 field
- Short Name:
- J/MNRAS/464/3357
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 610-MHz Giant Metrewave Radio Telescope observations of 0.84deg^2^ of the AMI001 field (centred on 00h23m10s, +31d53') with an rms noise of 18microJy/beam in the centre of the field. A total of 955 sources are detected, and 814 are included in the source count analysis. The source counts from these observations are consistent with previous work. We have used these data to study the spectral index distribution of a sample of sources selected at 15.7GHz from the recent deep extension to the Tenth Cambridge (10C) survey. The median spectral index, alpha, (where S{prop.to}nu^-alpha^^) between 0.08<S_15.7GHz/mJy<0.2 is 0.32+/-0.14, showing that star-forming galaxies, which have much steeper spectra, are not contributing significantly to this population. This is in contrast to several models, but in agreement with the results from the 10C ultra-deep source counts; the high-frequency sky therefore continues to be dominated by radio galaxies down to S_15.7GHz_=0.1mJy.
- ID:
- ivo://CDS.VizieR/J/AJ/154/169
- Title:
- GMRT observations of head-tail radio galaxies
- Short Name:
- J/AJ/154/169
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a study of seven large known head-tail radio galaxies based on observations using the Giant Metrewave Radio Telescope at 240 and 610 MHz. These observations are used to study the radio morphologies and distribution of the spectral indices across the sources. The overall morphology of the radio tails of these sources is suggestive of random motions of the optical host around the cluster potential. The presence of multiple bends and wiggles in several head-tail sources is possibly due to the precessing radio jets. We find steepening of the spectral index along the radio tails. The prevailing equipartition magnetic field also decreases along the radio tails of these sources. These steepening trends are attributed to the synchrotron aging of plasma toward the ends of the tails. The dynamical ages of these sample sources have been estimated to be ~10^8^ yr, which is a factor of six more than the age estimates from the radiative losses due to synchrotron cooling.
- ID:
- ivo://CDS.VizieR/J/A+A/551/A24
- Title:
- GMRT Radio Halo Cluster Survey diffuse sources
- Short Name:
- J/A+A/551/A24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To gain further insight on the origin of diffuse radio sources in galaxy clusters and their connection with cluster merger processes, we performed GMRT low frequency observations of the radio halos, relics and new candidates belonging to the GMRT Radio Halo Cluster Sample first observed at 610MHz. Our main aim was to investigate their observational properties and integrated spectrum at frequencies below 610MHz.
- 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).
- ID:
- ivo://CDS.VizieR/J/A+A/634/A41
- Title:
- G107.298+5.639 multi-frequency maser light curves
- Short Name:
- J/A+A/634/A41
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Periodic flares of maser emission are thought to be induced either by variations of the seed photon flux in young binary systems or the pump rate regulated by stellar and accretion luminosities. We seek to study the variability of four maser transitions of three different species in G107.298+5.639 to constrain the dominant mechanism of periodic flares. Light curves of the 6.7GHz methanol and 22.2GHz water vapour maser were obtained with the Torun 32m radio telescope over 39 and 34 cycles, respectively. The target was also monitored at the 1.6GHz hydroxyl transitions with the Nancay radio telescope over 13 cycles. All these maser lines were imaged using VLBI arrays. The study confirms alternating flares of the methanol and water masers with a period of 34.4d and reveals the synchronised behaviour of the methanol and hydroxyl masers in this source. The observed spatial distribution of the methanol maser cloudlets and the measured time delays of the flares of individual features imply a ring-like structure of radius 240au and thickness 30au. Internal proper motions indicate that the velocity of methanol cloudlets is dominated by a disc-wind component of about 5km/s. The methanol emission detected during only one VLBI observation is located in a region about 550 au from a central star, which also exhibits OH maser flares. The erratic appearance of methanol features can be related to a powering object of relatively low luminosity which, during some variability cycles, can excite molecules only in the nearest part of the disc. A careful analysis of the maser and infrared light curves reveal a strong correlation between the 6.7GHz line and the infrared flux densities supporting a radiative pumping of the maser. The synchronised behaviour of the hydroxyl 1665/1667MHz and 6.7GHz methanol transitions indicates a common pumping mechanism for the periodic flares of G107.298+5.639.
- 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/834/142
- Title:
- Gould's Belt Distances Survey (GOBELINS). II. OMC
- Short Name:
- J/ApJ/834/142
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of the Gould's Belt Distances Survey of young star-forming regions toward the Orion Molecular Cloud Complex. We detected 36 young stellar objects (YSOs) with the Very Large Baseline Array, 27 of which have been observed in at least three epochs over the course of two years. At least half of these YSOs belong to multiple systems. We obtained parallax and proper motions toward these stars to study the structure and kinematics of the Complex. We measured a distance of 388+/-5pc toward the Orion Nebula Cluster, 428+/-10pc toward the southern portion L1641, 388+/-10pc toward NGC 2068, and roughly ~420pc toward NGC 2024. Finally, we observed a strong degree of plasma radio scattering toward {lambda} Ori.
- ID:
- ivo://CDS.VizieR/J/ApJ/801/91
- Title:
- Gould's Belt Very Large Array survey. IV. Taurus
- Short Name:
- J/ApJ/801/91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multi-epoch radio study of the Taurus-Auriga star-forming complex made with the Karl G. Jansky Very Large Array at frequencies of 4.5GHz and 7.5GHz. We detect a total of 610 sources, 59 of which are related to young stellar objects (YSOs) and 18 to field stars. The properties of 56% of the young stars are compatible with non-thermal radio emission. We also show that the radio emission of more evolved YSOs tends to be more non-thermal in origin and, in general, that their radio properties are compatible with those found in other star-forming regions. By comparing our results with previously reported X-ray observations, we notice that YSOs in Taurus-Auriga follow a Gudel-Benz relation with {kappa}=0.03, as we previously suggested for other regions of star formation. In general, YSOs in Taurus-Auriga and in all the previous studied regions seem to follow this relation with a dispersion of ~1dex. Finally, we propose that most of the remaining sources are related with extragalactic objects but provide a list of 46 unidentified radio sources whose radio properties are compatible with a YSO nature.
- ID:
- ivo://CDS.VizieR/J/ApJ/790/49
- Title:
- Gould's Belt VLA survey. III. Orion region
- Short Name:
- J/ApJ/790/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a high-sensitivity (60{mu}Jy), large-scale (2.26deg^2^) survey obtained with the Karl G. Jansky Very Large Array as part of the Gould's Belt Survey program. We detected 374 and 354 sources at 4.5 and 7.5GHz, respectively. Of these, 148 are associated with previously known young stellar objects (YSOs). Another 86 sources previously unclassified at either optical or infrared wavelengths exhibit radio properties that are consistent with those of young stars. The overall properties of our sources at radio wavelengths such as their variability and radio to X-ray luminosity relation are consistent with previous results from the Gould's Belt Survey. Our detections provide target lists for follow-up Very Long Baseline Array radio observations to determine their distances as YSOs are located in regions of high nebulosity and extinction, making it difficult to measure optical parallaxes.
