J/A+A/602/A31 G29.37+0.1 610MHz image (Castelletti+, 2017)
Radio and X-ray properties of the source G29.37+0.1 linked to HESS J1844-030.
Castelletti G., Supan L., Petriella A., Giacani E., Joshi B.C.
<Astron. Astrophys. 602, A31 (2017)>
=2017A&A...602A..31C 2017A&A...602A..31C (SIMBAD/NED BibCode)
ADC_Keywords: Radio sources ; Gamma rays ; X-ray sources
Keywords: gamma rays: galaxies - radio continuum: galaxies - ISM: general -
X-rays: general
Abstract:
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.
Description:
Synchrotron emission from the region of the source named G29.37+0.1 as
observed by the Giant Metrewave Radio Telescope at 610MHz.
Objects:
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RA (2000) DE Designation(s)
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18 44 41.22 -03 05 34.6 G29.37+0.1 = AX J1844.6-0305
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 139 1 Fits image informations
G29.37-AA.SUBIM.fits 2880 1420 Fits image
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See also:
J/A+A/587/A71 : SNR G11.0-0.0 1.4GHz radio continuum image (Castelletti+, 2016)
Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 22 I3 --- Nx Number of pixels along X-axis
24- 26 I3 --- Ny Number of pixels along Y-axis
28- 37 A10 "date" Obs.date Observation date
39- 45 F7.3 MHz Freq Observed frequency
47- 50 I4 Kibyte size Size of FITS file
52- 71 A20 --- FileName Name of FITS file
73-139 A67 --- Title Title of the FITS file
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Acknowledgements:
Gabriela Castelletti, gcastell(at)iafe.uba.ar,
Institute of Astronomy and Space Physics, Argentina
(End) Gabriela Castelletti [IAFE, Argentina], Patricia Vannier [CDS] 06-Feb-2017