43 research outputs found
WATCAT: a tale of wide-angle tailed radio galaxies
We present a catalog of 47 wide-angle tailed radio galaxies (WATs), the
WATCAT; these galaxies were selected by combining observations from the
National Radio Astronomy Observatory/Very Large Array Sky Survey (NVSS), the
Faint Images of the Radio Sky at Twenty-Centimeters (FIRST), and the Sloan
Digital Sky Survey (SDSS), and mainly built including a radio morphological
classification. We included in the catalog only radio sources showing two-sided
jets with two clear "warmspots" (i.e., jet knots as bright as 20% of the
nucleus) lying on the opposite side of the radio core, and having classical
extended emission resembling a plume beyond them. The catalog is limited to
redshifts z 0.15, and lists only sources with radio emission extended
beyond 30 kpc from the host galaxy. We found that host galaxies of WATCAT
sources are all luminous (-20.5 Mr -23.7), red early-type
galaxies with black hole masses in the range M M. The spectroscopic classification indicates that they
are all low-excitation galaxies (LEGs). Comparing WAT multifrequency properties
with those of FRI and FRII radio galaxies at the same redshifts, we conclude
that WATs show multifrequency properties remarkably similar to FRI radio
galaxies, having radio power of typical FRIIs
Deciphering the Large-Scale Environment of Radio Galaxies in the Local Universe II. A Statistical Analysis of Environmental Properties
In our previous analysis we investigated the large-scale environment of two
samples of radio galaxies (RGs) in the local Universe (i.e. with redshifts
z<0.15), classified as FR I and FR II on the basis of their radio morphology.
The analysis was carried out using i) extremely homogeneous catalogs and ii) a
new method, known as cosmological overdensity, to investigate their large-scale
environments. We concluded that, independently by the shape of their radio
extended structure, RGs inhabit galaxy-rich large-scale environments with
similar characteristics and richness. In the present work, we first highlight
additional advantages of our procedure, that does not suffer cosmological
biases and/or artifacts, and then we carry out an additional statistical test
to strengthen our previous results. We also investigate properties of RG
environments using those of the cosmological neighbors. We find that
large-scale environments of both FRIs and FRIIs are remarkably similar and
independent on the properties of central RG. Finally, we highlight the
importance of comparing radio sources in the same redshift bins to obtain a
complete overview of their large-scale environments.Comment: 15 pages, 21 figures, 3 tables, ApJS in press (pre-proof version
MiRNAs as biomarkers of phenotype in neutral lipid storage disease with myopathy
BACKGROUND:
Neutral lipid storage disease with myopathy (NLSDM) is a rare lipid metabolism disorder. In this study, we evaluated some circulating miRNAs levels in serum samples and the MRI of three affected siblings.
METHODS:
Three members of one NLSDM family were identified: two brothers and one sister. Muscles of lower and right upper extremities were studied by MRI. Expression profile of miRNAs, obtained from serum samples, was detected using qRT-PCR.
RESULTS:
Two brothers presented with progressive skeletal myopathy, while the sister had severe hepatosteatosis and diabetes. NLSDM patients showed a significant increase of muscle-specific miRNAs expression compared with healthy subjects. We found a correlation between hepatic damage and elevation of miRNAs expression profile of liver origin.
CONCLUSIONS:
The dysregulation of miRNAs might represent an indicator of skeletal and hepatic damage and it might be useful to monitor the progression of NLSDM
Investigating the large-scale environment of wide-angle tailed radio galaxies in the local Universe
We present a statistical analysis of the large-scale (up to 2 Mpc)
environment of an homogeneous and complete sample, both in radio and optical
selection, of wide-angle tailed radio galaxies (WATs) in the local Universe
(i.e., with redshifts 0.15). The analysis is carried out using the
parameters obtained from cosmological neighbors within 2 Mpc of the target
source. Results on WATs large-scale environments are then compared with that of
Fanaroff-Riley type I (FR Is) and type II (FR IIs) radio galaxies, listed in
two others homogeneous and complete catalogs, and selected with the same
criterion adopted for the WATs catalog. We obtain indication that at low
redshift WATs inhabit environments with a larger number of galaxies than that
of FR Is and FR IIs. In the explored redshift range, the physical size of the
galaxy group/cluster in which WATs reside appears to be almost constant with
respect to FR Is and FR IIs, being around 1 Mpc. From the distribution of the
concentration parameter, defined as the ratio between the number of
cosmological neighbors lying within 500 kpc and within 1 Mpc, we conclude that
WATs tend to inhabit the central region of the group/cluster in which they
reside, in agreement with the general paradigm that WATs are the cluster BCG.Comment: 8 pages, 5 figures, 1 table. Accepted for publication on A&
Hidden Treasures in the Unknown 3CR Extragalactic Radio Sky: A Multiwavelength Approach
We present the analysis of multiwavelength observations of seven extragalactic radio sources, listed as unidentified in the Third Cambridge Revised Catalog (3CR). X-ray observations, performed during Chandra Cycle 21, were compared to Very Large Array (VLA), Wide-field Infrared Survey Explorer, and Pan-STARRS observations in the radio, infrared, and optical bands, respectively. All sources in this sample lack a clear optical counterpart, and are thus missing their redshift and optical classification. In order to confirm the X-ray and infrared radio counterparts of core and extended components, here we present for the first time radio maps obtained manually reducing VLA archival data. As in previous papers on the Chandra X-ray snapshot campaign, we report X-ray detections of radio cores and two sources, out of the seven presented here, are found to be members of galaxy clusters. For these two cluster sources (namely, 3CR 409 and 3CR 454.2), we derived surface brightness profiles in four directions. For all seven sources, we measured X-ray intensities of the radio sources and we also performed standard X-ray spectral analysis for the four sources (namely, 3CR 91, 3CR 390, 3CR 409, and 3CR 428) with the brightest nuclei (more than 400 photons in the 2\u27\u27 nuclear region). We also detected extended X-ray emission around 3CR 390 and extended X-ray emission associated with the northern jet of 3CR 158. This paper represents the first attempt to give a multiwavelength view of the unidentified radio sources listed in the 3CR catalog
Peering into the extended X-ray emission on megaparsec scale in 3C 187
Context. The diffuse X-ray emission surrounding radio galaxies is generally interpreted either as due to inverse Compton scattering of nonthermal radio-emitting electrons on the cosmic microwave background (IC/CMB), or as due to thermal emission arising from the hot gas of the intergalactic medium (IGM) permeating galaxy clusters hosting such galaxies, or as a combination of both. In this work, we present an imaging and spectral analysis of Chandra observations for the radio galaxy 3C 187 to investigate its diffuse X-ray emission and constrain the contribution of these various physical mechanisms.
Aims. The main goals of this work are the following: (i) to evaluate the extension of the diffuse X-ray emission from this source; (ii) to investigate the two main processes, IC/CMB and thermal emission from the IGM, which can account for the origin of this emission; and (iii) to test the possibility that 3C 187 belongs to a cluster of galaxies, which can account for the observed diffuse X-ray emission.
Methods. To evaluate the extension of the X-ray emission around 3C 187, we extracted surface flux profiles along and across the radio axis. We also extracted X-ray spectra in the region of the radio lobes and in the cross-cone region to estimate the contribution of the nonthermal (IC/CMB) and thermal (IGM) processes to the observed emission, making use of radio (VLA and GMRT) data to investigate the multiwavelength emission arising from the lobes. We collected Pan-STARRS photometric data to investigate the presence of a galaxy cluster hosting 3C 187, looking for the presence of a “red sequence” in the source field in the form of a tight clustering of galaxies in the color space. In addition, we made use of observations performed with the COSMOS spectrograph at the Victor Blanco Telescope to estimate the redshift of the sources in the field of 3C 187 to verify if they are gravitationally bound, as we would expect in a cluster of galaxies.
Results. The diffuse X-ray emission around 3C 187 is found to extend in the soft 0.3 − 3 keV band up to ∼850 kpc along the radio lobe direction and ∼530 kpc in the cross-cone direction, and it appears enhanced in correspondence with the radio lobes. Spectral X-ray analysis in the cross-cones indicates a thermal origin for the emission in this region with a temperature ∼4 keV. In the radio lobes, the X-ray spectral analysis in combination with the radio data suggests a dominant IC/CMB radiation in these regions, however we do not rule out a significant thermal contribution. Assuming that the radiation observed in the radio lobes is due to the IGM, the emission from the N and S cones can be interpreted as arising from hot gas with temperatures of ∼3 keV and ∼5 keV, respectively, and found to be in pressure equilibrium with the surrounding gas. Using Pan-STARRS optical data we found that 3C 187 belongs to a red sequence of ∼40 optical sources in the field whose color distribution is significantly different from background sources. We were able to collect optical spectra for only one of these cluster candidates and for 22 field (i.e., noncluster candidates) sources. While the latter show stellar spectra, the former feature a galactic spectrum with a redshift close to 3C 187 nucleus.
Conclusions. The diffuse X-ray emission around 3C 187 is elongated along the radio axis and enhanced in correspondence with the radio lobes. This indicates a morphological connection between the emission in the two energy bands and thus suggests a dominating IC/CMB mechanism in these regions. This scenario is reinforced by multiwavelength radio X-ray emission, which in these regions is compatible with IC/CMB radiation. The X-ray spectral analysis however does not rule out a significant contribution to the observed emission from thermal gas, which would be able to emit over tens of gigayears and in pressure equilibrium with the surroundings. Optical data indicate that 3C 187 may belong to a cluster of galaxies, whose IGM would contribute to the X-ray emission observed around the source. Additional X-ray and optical spectroscopic observations are however needed to secure these results and get a more clear picture of the physical processes at play in 3C 187
Peering Into the Extended X-ray Emission on Megaparsec Scale in 3C 187
Context. The diffuse X-ray emission surrounding radio galaxies is generally
interpreted either as due to inverse Compton scattering of non-thermal
radio-emitting electrons on the Cosmic Microwave Background (IC/CMB), or as the
thermal emission arising from the hot gas of the intergalactic medium (IGM)
permeating galaxy clusters hosting such galaxies, or as a combination of both.
In this work we present an imaging and spectral analysis of Chandra
observations for the radio galaxy 3C 187 to investigate its diffuse X-ray
emission and constrain the contribution of these different physical mechanisms.
Aims. The main goals of this work are: (i) to evaluate the extension of the
diffuse X-ray emission from this source, (ii) to investigate the two main
processes that can account for its origin - IC/CMB and thermal emission from
the IGM - and (iii) to test the possibility for 3C 187 to belong to a cluster
of galaxies, that can account for the observed diffuse X-ray emission. Methods.
To evaluate the extension of the X-ray emission around 3C 187 we extracted
surface flux profiles along and across the radio axis. We also extracted X-ray
spectra in the region of the radio lobes and in the cross-cone region to
estimate the contribution of the non-thermal (IC/CMB) and thermal (IGM)
processes to the observed emission, making use of radio (VLA and GMRT) data to
investigate the multi-wavelength emission arising from the lobes. We collected
Pan-STARRS photometric data to investigate the presence of a galaxy cluster
hosting 3C 187, looking for the presence of a "red sequence" in the source
field in the form of a tight clustering of the galaxies in the color space...Comment: 32 pages, 13 figures, accepted for publication on A&A on 12/19/202
Peering into the extended X-ray emission on megaparsec scale in 3C 187
Context. The diffuse X-ray emission surrounding radio galaxies is generally interpreted either as due to inverse Compton scattering of nonthermal radio-emitting electrons on the cosmic microwave background (IC/CMB), or as due to thermal emission arising from the hot gas of the intergalactic medium (IGM) permeating galaxy clusters hosting such galaxies, or as a combination of both. In this work, we present an imaging and spectral analysis of Chandra observations for the radio galaxy 3C 187 to investigate its diffuse X-ray emission and constrain the contribution of these various physical mechanisms. Aims. The main goals of this work are the following: (i) to evaluate the extension of the diffuse X-ray emission from this source; (ii) to investigate the two main processes, IC/CMB and thermal emission from the IGM, which can account for the origin of this emission; and (iii) to test the possibility that 3C 187 belongs to a cluster of galaxies, which can account for the observed diffuse X-ray emission. Methods. To evaluate the extension of the X-ray emission around 3C 187, we extracted surface flux profiles along and across the radio axis. We also extracted X-ray spectra in the region of the radio lobes and in the cross-cone region to estimate the contribution of the nonthermal (IC/CMB) and thermal (IGM) processes to the observed emission, making use of radio (VLA and GMRT) data to investigate the multiwavelength emission arising from the lobes. We collected Pan-STARRS photometric data to investigate the presence of a galaxy cluster hosting 3C 187, looking for the presence of a "red sequence"in the source field in the form of a tight clustering of galaxies in the color space. In addition, we made use of observations performed with the COSMOS spectrograph at the Victor Blanco Telescope to estimate the redshift of the sources in the field of 3C 187 to verify if they are gravitationally bound, as we would expect in a cluster of galaxies. Results. The diffuse X-ray emission around 3C 187 is found to extend in the soft 0.3 - 3 keV band up to ∼850 kpc along the radio lobe direction and ∼530 kpc in the cross-cone direction, and it appears enhanced in correspondence with the radio lobes. Spectral X-ray analysis in the cross-cones indicates a thermal origin for the emission in this region with a temperature ∼4 keV. In the radio lobes, the X-ray spectral analysis in combination with the radio data suggests a dominant IC/CMB radiation in these regions, however we do not rule out a significant thermal contribution. Assuming that the radiation observed in the radio lobes is due to the IGM, the emission from the N and S cones can be interpreted as arising from hot gas with temperatures of ∼3 keV and ∼5 keV, respectively, and found to be in pressure equilibrium with the surrounding gas. Using Pan-STARRS optical data we found that 3C 187 belongs to a red sequence of ∼40 optical sources in the field whose color distribution is significantly different from background sources. We were able to collect optical spectra for only one of these cluster candidates and for 22 field (i.e., noncluster candidates) sources. While the latter show stellar spectra, the former feature a galactic spectrum with a redshift close to 3C 187 nucleus. Conclusions. The diffuse X-ray emission around 3C 187 is elongated along the radio axis and enhanced in correspondence with the radio lobes. This indicates a morphological connection between the emission in the two energy bands and thus suggests a dominating IC/CMB mechanism in these regions. This scenario is reinforced by multiwavelength radio X-ray emission, which in these regions is compatible with IC/CMB radiation. The X-ray spectral analysis however does not rule out a significant contribution to the observed emission from thermal gas, which would be able to emit over tens of gigayears and in pressure equilibrium with the surroundings. Optical data indicate that 3C 187 may belong to a cluster of galaxies, whose IGM would contribute to the X-ray emission observed around the source. Additional X-ray and optical spectroscopic observations are however needed to secure these results and get a more clear picture of the physical processes at play in 3C 187
The 3CR Chandra snapshot survey: extragalactic radio sources with 0.51.0
This paper presents the analysis of Chandra X-ray snapshot observations of a
subsample of the extragalactic sources listed in the revised Third Cambridge
radio catalog (3CR), previously lacking X-ray observations and thus observed
during Chandra Cycle 15. This data set extends the current Chandra coverage of
the 3CR extragalactic catalog up to redshift =1.0. Our sample includes 22
sources consisting of one compact steep spectrum (CSS) source, three quasars
(QSOs), and 18 FR\,II radio galaxies. As in our previous analyses, here we
report the X-ray detections of radio cores and extended structures (i.e.,
knots, hotspots and lobes) for all sources in the selected sample. We measured
their X-ray intensities in three energy ranges: soft (0.5--1 keV), medium (1--2
keV) and hard (2-7 keV) and we also performed standard X-ray spectral analysis
for brighter nuclei. All radio nuclei in our sample have an X-ray counterpart.
We also discovered X-ray emission associated with the eastern knot of 3CR\,154,
with radio hotspots in 3CR\,41, 3CR\,54 and 3CR\,225B and with the southern
lobe of 3CR\,107. Extended X-ray radiation around the nuclei 3CR\,293.1 and
3CR\,323 on a scale of few tens kpc was also found. X-ray extended emission,
potentially arising from the hot gas in the intergalactic medium and/or due to
the high energy counterpart of lobes, is detected for 3CR\,93, 3CR\,154,
3CR\,292 and 3CR\, 323 over a few hundreds kpc-scale. Finally, this work also
presents an update on the state-of-the-art of Chandra and XMM-Newton
observations for the entire 3CR sample.Comment: 25 pages, 6 tables, 27 figures, ApJS accepted for publication
(pre-proof version
The 3CR extragalactic survey at 1.01.5
The aim of this paper is to present an analysis of newly acquired X-ray
observations of 16 extragalactic radio sources, listed in the Third Cambridge
Revised (3CR) catalog, and not previously observed by Chandra. Observations
were performed during Chandra Cycle 17, extending X-ray coverage for the 3CR
extragalactic catalog up to =1.5. Among the 16 targets, two lie at 0.5
(i.e., 3CR27, at =0.184 and 3CR69, at =0.458), all the remaining 14 have
redshifts between 1.0 and 1.5. In the current sample there are three compact
steep spectrum (CSS) sources, three quasars and an FRI radio galaxy, while the
other nine are FRII radio galaxies. All radio sources have an X-ray
counterpart. We measured nuclear X-ray fluxes as well as X-ray emission
associated with radio jet knots, hotspots or lobes in three energy bands: soft
(0.5-1 keV), medium (1-2 keV) and hard (2-7 keV). We also performed standard
X-ray spectral analysis for the four brightest nuclei. We discovered X-ray
emission associated with: the radio lobe of 3CR124; a hotspot of the quasar
3CR220.2; another hotspot of the radio galaxy 3CR238; and the jet knot of
3CR297. We also detected extended X-ray emission around the nuclear region of
3CR124 and 3CR297 on scales of several tens of kpc. Finally, we present an
update on the X-ray observations performed with Chandra and XMM-Newton on the
entire 3CR extragalactic catalog.Comment: 25 pages, 19 figures, 5 tables, pre-proof version, published on the
Astrophysical Journal Supplement serie