X-ray source population in the polar ring galaxy NGC 660 as observed by Chandra

2021 ◽  
Vol 21 (11) ◽  
pp. 289
Author(s):  
Nurnabilah Nazri ◽  
Adlyka Annuar
Keyword(s):  
Threshold Value ◽  
Population Based ◽  
Source Spectrum ◽  
Source Population ◽  
Ratio Distribution ◽  
X Ray ◽  
Star Forming ◽  
Polar Ring ◽  
The Galaxy ◽  
Ring Galaxies

Abstract We present Chandra observations of the nearby polar ring galaxy NGC 660 to study its X-ray source population. Based on our analysis, we detected a total of 23 X-ray sources in the 0.5−8 keV band, with luminosities ranging from ∼1037 to ∼1039 erg s−1. Twenty-two of these sources are located off-nuclear and have luminosities below the ultraluminous X-ray source (ULX) threshold value of L 0.5−8 keV < 1039 erg s−1, suggesting that they are likely to be X-ray binary (XRB) candidates. The remaining source is located at the center of the galaxy, suggesting it is an active galactic nucleus (AGN). However, we estimated that four of the detected sources could be associated with background objects. Based on the source count rates in each of the Chandra observations, we found evidence for variability in nine of the 23 sources, including the AGN. However, further investigation with spectral analysis suggested no significant differences in the AGN luminosities between the observations. The X-ray luminosity distribution of the galaxy was found to be generally lower than that expected from previous studies on star forming and collisional ring galaxies. No ULX was also detected in the galaxy, in contrast with what was expected from the galaxyʼs SFR and metallicity (i.e., SFR = 14.43 ± 0.19 M ⊙ yr−1 and Z = 0.94 ± 0.01 Z ⊙, respectively). These results suggest a deficit in the X-ray sources detected. Based on source hardness ratio distribution, we found evidence that the fainter sources have a harder source spectrum, indicating higher absorption. This further suggests that there could be more X-ray sources that were not detected in the galaxy due to significant obscuration.

scholarly journals The role of AGN activity in the building up of the BCG at z ∼ 1.6

2019 ◽  
Vol 15 (S356) ◽  
pp. 280-284
Author(s):  
Angela Bongiorno ◽  
Andrea Travascio
Keyword(s):  
Galaxy Cluster ◽  
Cluster Galaxy ◽  
X Ray ◽  
Groups Of Galaxies ◽  
Star Forming ◽  
The Core ◽  
The Galaxy ◽  
Multi Wavelength

AbstractXDCPJ0044.0-2033 is one of the most massive galaxy cluster at z ∼1.6, for which a wealth of multi-wavelength photometric and spectroscopic data have been collected during the last years. I have reported on the properties of the galaxy members in the very central region (∼ 70kpc × 70kpc) of the cluster, derived through deep HST photometry, SINFONI and KMOS IFU spectroscopy, together with Chandra X-ray, ALMA and JVLA radio data.In the core of the cluster, we have identified two groups of galaxies (Complex A and Complex B), seven of them confirmed to be cluster members, with signatures of ongoing merging. These galaxies show perturbed morphologies and, three of them show signs of AGN activity. In particular, two of them, located at the center of each complex, have been found to host luminous, obscured and highly accreting AGN (λ = 0.4−0.6) exhibiting broad Hα line. Moreover, a third optically obscured type-2 AGN, has been discovered through BPT diagram in Complex A. The AGN at the center of Complex B is detected in X-ray while the other two, and their companions, are spatially related to radio emission. The three AGN provide one of the closest AGN triple at z > 1 revealed so far with a minimum (maximum) projected distance of 10 kpc (40 kpc). The discovery of multiple AGN activity in a highly star-forming region associated to the crowded core of a galaxy cluster at z ∼ 1.6, suggests that these processes have a key role in shaping the nascent Brightest Cluster Galaxy, observed at the center of local clusters. According to our data, all galaxies in the core of XDCPJ0044.0-2033 could form a BCG of M* ∼ 1012Mȯ hosting a BH of 2 × 108−109Mȯ, in a time scale of the order of 2.5 Gyrs.

scholarly journals Redshift measurement through star formation

2019 ◽  
Vol 629 ◽  
pp. A7
Author(s):  
Mikkel O. Lindholmer ◽  
Kevin A. Pimbblet
Keyword(s):  
Star Formation ◽  
Galaxy Clusters ◽  
Main Sequence ◽  
Formation Rate ◽  
Sloan Digital Sky Survey ◽  
X Ray ◽  
Star Forming ◽  
Sky Survey ◽  
The Galaxy ◽  
Galaxy Population

In this work we use the property that, on average, star formation rate increases with redshift for objects with the same mass – the so called galaxy main sequence – to measure the redshift of galaxy clusters. We use the fact that the general galaxy population forms both a quenched and a star-forming sequence, and we locate these ridges in the SFR–M⋆ plane with galaxies taken from the Sloan Digital Sky Survey in discrete redshift bins. We fitted the evolution of the galaxy main sequence with redshift using a new method and then subsequently apply our method to a suite of X-ray selected galaxy clusters in an attempt to create a new distance measurement to clusters based on their galaxy main sequence. We demonstrate that although it is possible in several galaxy clusters to measure the main sequences, the derived distance and redshift from our galaxy main sequence fitting technique has an accuracy of σz = ±0.017 ⋅ (z + 1) and is only accurate up to z ≈ 0.2.

scholarly journals A Survey of X-ray Point Sources in the Magellanic Clouds

1999 ◽  
Vol 192 ◽  
pp. 100-103
Author(s):  
A. P. Cowley ◽  
P. C. Schmidtke ◽  
V. A. Taylor ◽  
T.K. McGrath ◽  
J. B. Hutchings ◽  
...  
Keyword(s):  
Stellar Population ◽  
Population Based ◽  
Magellanic Clouds ◽  
Point Sources ◽  
High Mass ◽  
Be Stars ◽  
X Ray ◽  
The Galaxy ◽  
Low Mass ◽  
X Ray Binaries

In this study we compare the global populations of stellar X-ray sources in the LMC, SMC, and the Galaxy. After removing foreground stars and background AGN from the samples, the relative numbers of the various types of X-ray point sources within the LMC and SMC are similar, but differ markedly from those in the Galaxy. The Magellanic Clouds are rich in high-mass X-ray binaries (HMXB), especially those containing rapidly rotating Be stars. However, the LMC and SMC both lack the large number of low-mass X-ray binaries (LMXB) found in the Milky Way, which are known to represent a very old stellar population based on their kinematics, chemical composition, and spatial distribution.

scholarly journals Deep GMRT 610 MHz observations of the ELAIS N1 field: catalogue and source counts

2019 ◽  
Vol 491 (1) ◽  
pp. 1127-1145 ◽  
Author(s):  
E F Ocran ◽  
A R Taylor ◽  
M Vaccari ◽  
C H Ishwara-Chandra ◽  
I Prandoni
Keyword(s):  
Spectral Index ◽  
Low Frequency ◽  
Source Population ◽  
X Ray ◽  
Star Forming ◽  
Density Distributions ◽  
Deep Image ◽  
Frequency Source ◽  
Minimum Noise ◽  
Good Agreement

ABSTRACT This is the first of a series of papers based on sensitive 610 MHz observations of the ELAIS N1 field, using the Giant Metrewave Radio Telescope. We describe the observations, processing and source catalogue extraction from a deep image with area of 1.86 deg2 and minimum noise of ∼7.1 μJy beam−1. We compile a catalogue of 4290 sources with flux densities in the range of 28.9 μJy– 0.503 Jy and derive the Euclidean-normalized differential source counts for sources with flux densities brighter than $\rm {35.5\, \mu Jy}$. Our counts show a flattening at 610 MHz flux densities below 1 mJy. Below the break the counts are higher than previous observations at this frequency, but generally consistent with recent models of the low-frequency source population. The radio catalogue is cross-matched against multiwavelength data leading to identifications for 92 per cent and reliable redshifts for 72 per cent of our sample, with 19 per cent of the redshifts based on spectroscopy. For the sources with redshifts, we use radio and X-ray luminosity, optical spectroscopy and mid-infrared colours to search for evidence of the presence of an active galactic nucleus (AGN). We compare our identifications to predictions of the flux density distributions of star-forming galaxies (SFGs) and AGN, and find a good agreement assuming the majority of the sources without redshifts are SFGs. We derive spectral index distributions for a sub-sample. The majority of the sources are steep spectra, with a median spectral index that steepens with frequency: $\mathrm{\alpha ^{610}_{325}\, =\, -0.80\, \pm \, 0.29}$, $\mathrm{\alpha ^{610}_{1400}\, =\, -0.83\, \pm \, 0.31}$, and $\mathrm{\alpha ^{610}_{5000}\, =\, -1.12\, \pm \, 0.15}$.

scholarly journals Star-forming complexes in the polar ring galaxy NGC660

2017 ◽  
Vol 26 (1) ◽  
Author(s):  
Ksenia I. Smirnova ◽  
Dmitri S. Wiebe ◽  
Alexei V. Moiseev
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Star Forming ◽  
Polar Ring ◽  
Star Forming Regions ◽  
Disk Star ◽  
Dust Mass ◽  
The Galaxy ◽  
Galaxy Disk

AbstractGalaxies with polar rings consist of two subsystems, a disk and a ring, which rotate almost in orthogonal planes. In this paper, we analyze the parameters characterizing the composition of the interstellar medium and star formation in star-forming complexes belonging to polar ring galaxy NGC660. We show that star-forming regions in the ring of the galaxy are distinctly different from those in the galaxy disk. They possess substantially lower infrared luminosities, which is indicative of less dust mass in these regions than in a typical disk star-forming region. UV and Hα luminosities also appear to be lower in the ring, which is likely a consequence of its relatively recent formation.

scholarly journals The nuclear region of NGC 613 – I. Multiwavelength analysis

2020 ◽  
Vol 492 (4) ◽  
pp. 5121-5140 ◽  
Author(s):  
Patrícia da Silva ◽  
R B Menezes ◽  
J E Steiner
Keyword(s):  
Supernova Remnants ◽  
Near Infrared ◽  
H Ii Regions ◽  
Nuclear Region ◽  
Radio Telescopes ◽  
X Ray ◽  
Star Forming ◽  
Dust Extinction ◽  
The Galaxy ◽  
Variable Point

ABSTRACT In this paper, we report a detailed study with a variety of data from optical, near-infrared, X-ray, and radio telescopes of the nuclear region of the galaxy NGC 613 with the aim of understanding its complexity. We detected an extended stellar emission in the nucleus that, at first, appears to be, in the optical band, two stellar nuclei separated by a stream of dust. The active galactic nucleus (AGN) is identified as a variable point-like source between these two stellar components. There is a central hard X-ray emission and an extended soft X-ray emission that closely coincides with the ionization cone, as seen in the [O iii]λ5007 emission. The centroid of the [O i]λ6300 emission does not coincide with the AGN, being shifted by 0.24 arcsec towards the ionization cone; this shift is probably caused by a combination of differential dust extinction together with emission and reflection in the ionization cone. The optical spectra extracted from the central region are typical of low-ionization nuclear emission-line regions. We also identify 10 H ii regions, eight of them in a star-forming ring that is visible in Br γ, [Fe ii]λ16436, and molecular CO(3-2) images observed in previous studies. Such a ring also presents weak hard X-ray emission, probably associated with supernova remnants, not detected in other studies. The position of the AGN coincides with the centre of a nuclear spiral (detected in previous works) that brings gas and dust from the bar to the nucleus, causing the high extinction in this area.

scholarly journals A Chandra study of the morphological structure of the Wolf-Rayet dwarf starburst galaxy NGC 4214

2003 ◽  
Vol 212 ◽  
pp. 720-721
Author(s):  
Joanna M. Hartwell ◽  
Ian R. Stevens ◽  
David K. Strickland ◽  
Timothy M. Heckman
Keyword(s):  
Morphological Structure ◽  
Young Star ◽  
Starburst Galaxy ◽  
X Ray ◽  
Star Forming ◽  
Star Forming Regions ◽  
The Galaxy ◽  
Starburst Regions

We present results from a Chandra X-ray observation of the dwarf starburst galaxy NGC 4214, a galaxy containing several young star forming regions. Starburst regions are known to be associated with diffuse X-ray emission, and in this case X-ray emission from the galaxy shows an interesting morphological structure with a bright X-ray ring of emission within the galaxy.

scholarly journals Polar ring galaxies in the Galaxy Zoo

2012 ◽  
Vol 422 (3) ◽  
pp. 2386-2398 ◽  
Author(s):  
Ido Finkelman ◽  
José G. Funes S. J. ◽  
Noah Brosch
Keyword(s):  
Polar Ring ◽  
The Galaxy ◽  
Ring Galaxies

scholarly journals A ULX and a giant cloud collision in M 99

2006 ◽  
Vol 2 (S238) ◽  
pp. 455-456
Author(s):  
Roberto Soria ◽  
Diane Sonya Wong
Keyword(s):  
Formation Rate ◽  
Virgo Cluster ◽  
Very Large Array ◽  
X Ray ◽  
Star Forming ◽  
Star Forming Regions ◽  
Tidal Interactions ◽  
The Galaxy ◽  
Photon Index ◽  
Hard Spectrum

AbstractThe Sc galaxy M 99 in the Virgo Cluster has been strongly affected by recent tidal interactions, responsible for an asymmetric spiral pattern and a high star formation rate (∼ 10 M⊙ yr−1). We studied the galaxy with XMM-Newton, Keck and the Very Large Array (VLA). The inner disk is dominated by hot plasma with a total X-ray luminosity ≈ 1041 erg s−1. At the outskirts of the galaxy, away from the main star-forming regions, there is an ultraluminous X-ray source (ULX) with an X-ray luminosity ≈ 2 × 1040 erg s−1 and a hard spectrum (power-law photon index Γ ≈ 1.7). This source is close to the location where a massive H I cloud appears to be falling onto the M 99 disk at a relative speed > 100 km s−1. The infalling gas may have been stripped from the nearby “dark galaxy” candidate VIRGOHI 21. We speculate there may be a relation between collisional events, infall of metal-poor gas clouds, and ULX formation.

scholarly journals GAMA/XXL: X-ray point sources in low-luminosity galaxies in the GAMA G02/XXL-N field

2021 ◽  
Vol 502 (2) ◽  
pp. 3101-3112
Author(s):  
E Nwaokoro ◽  
S Phillipps ◽  
A J Young ◽  
I Baldry ◽  
A Bongiorno ◽  
...  
Keyword(s):  
Positional Information ◽  
Point Sources ◽  
High Mass ◽  
X Ray ◽  
Star Forming ◽  
Flux Limit ◽  
The Galaxy ◽  
Low Mass ◽  
Mass Assembly ◽  
X Ray Binaries

ABSTRACT Relatively few X-ray sources are known that have low-mass galaxies as hosts. This is an important restriction on studies of active galactic nuclei (AGNs), hence black holes, and of X-ray binaries (XRBs) in low-mass galaxies; addressing it requires very large samples of both galaxies and X-ray sources. Here, we have matched the X-ray point sources found in the XXL-N field of the XXL survey (with an X-ray flux limit of ∼6 × 10−15 erg s−1 cm−2 in the [0.5–2] keV band) to galaxies with redshifts from the Galaxy And Mass Assembly (GAMA) G02 survey field (down to a magnitude limit r = 19.8) in order to search for AGNs and XRBs in GAMA galaxies, particularly those of low optical luminosity or stellar mass (fainter than Mr = −19 or $M_* \lesssim 10^{9.5}\, \mathrm{M}_{\odot }$). Out of a total of 1200 low-mass galaxies in the overlap region, we find a total of 28 potential X-ray source hosts, though this includes possible background contaminants. From a combination of photometry (optical and infrared colours), positional information, and optical spectra, we deduce that most of the ≃20 X-ray sources genuinely in low-mass galaxies are high-mass X-ray binaries in star-forming galaxies. None of the matched sources in a low-mass galaxy has a BPT classification as an AGN, and even ignoring this requirement, none passes both criteria of close match between the X-ray source position and optical galaxy centre (separation ≤3 arcsec) and high [O iii] line luminosity (above 1040.3 erg s−1).

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