327 research outputs found
A Multi-Wavelength Study of the Western Lobe of W50 Powered by the Galactic Microquasar SS 433
W50 remains the only supernova remnant (SNR) confirmed to harbor a
microquasar: the powerful enigmatic source SS 433. Our past study of this
fascinating SNR revealed two X-ray lobes distorting the radio shell as well as
non-thermal X-rays at the site of interaction between the SS 433 eastern jet
and the eastern lobe of W50. In this paper we present the results of a 75 ksec
CHANDRA ACIS-I observation of the peak of W50-west targeted to 1) determine the
nature of the X-ray emission and 2) correlate the X-ray emission with that in
the radio and infrared domains. We have confirmed that at the site of
interaction between the western jet of SS 433 and dense interstellar gas the
X-ray emission is non-thermal in nature. The helical pattern observed in radio
is also seen with CHANDRA. No correlation was found between the infrared and
X-ray emission.Comment: A refereed publication, submitted Sept. 30, 2004, accepted Jan. 12,
2005, to appear in Advances in Space Research. 7 pages, including 4 figures
(3 color) & 1 table (the resolution of most figures has been reduced for
astro-ph submission only). A gzipped postscript or pdf version of the paper
with high-resolution images can be downloaded from:
http://aurora.physics.umanitoba.ca/~moldowan/Astro-Ph
XMM-Newton, Chandra, and CGPS observations of the Supernova Remnants G85.4+0.7 and G85.9-0.6
We present an XMM-Newton detection of two low radio surface brightness SNRs,
G85.4+0.7 and G85.9-0.6, discovered with the Canadian Galactic Plane Survey
(CGPS). High-resolution XMM-Newton images revealing the morphology of the
diffuse emission, as well as discrete point sources, are presented and
correlated with radio and Chandra images. The new data also permit a
spectroscopic analysis of the diffuse emission regions, and a spectroscopic and
timing analysis of the point sources. Distances have been determined from HI
and CO data to be 3.5 +/- 1.0 kpc for SNR G85.4+0.7 and 4.8 +/- 1.6 kpc for SNR
G85.9-0.6. The SNR G85.4+0.7 is found to have a temperature of ~12-13 MK and a
0.5-2.5 keV luminosity of ~1-4 x 10^33 D(3.5)^2 erg/s (where D(3.5) is the
distance in units of 3.5 kpc), with an electron density n_e of
~0.07-0.16(fD(3.5))^-1/2 cm^-3 (where f is the volume filling factor), and a
shock age of ~9-49(fD(3.5))^1/2 kyr. The SNR G85.9-0.6 is found to have a
temperature of ~15-19 MK and a 0.5-2.5 keV luminosity of ~1-4 x 10^34 D(4.8)^2
erg/s (where D(4.8) is the distance in units of 4.8 kpc), with an electron
density n_e of ~0.04-0.10(fD(4.8))^-1/2 cm^-3 and a shock age of
~12-42(fD(4.8))^1/2 kyr. Based on the data presented here, none of the point
sources appears to be the neutron star associated with either SNR.Comment: 30 pages using emulateapj, 16 figures with quality reduced for
astro-ph only. The original version with high-resolution figures can be
downloaded from:
http://www.physics.umanitoba.ca/~samar/astro-ph/G85s-ms09102007.pdf To appear
in ApJ (Jan 20 2008 issue, v673, n1
Using Chandra to Unveil the High-Energy Properties of the High-Magnetic Field Radio Pulsar J1119-6127
(shortened) PSR J1119-6127 is a high magnetic field (B=4.1E13 Gauss), young
(<=1,700 year-old), and slow (P=408 ms) radio pulsar associated with the
supernova remnant (SNR) G292.2-0.5. In 2003, Chandra allowed the detection of
the X-ray counterpart of the radio pulsar, and provided the first evidence for
a compact pulsar wind nebula (PWN). We here present new Chandra observations
which allowed for the first time an imaging and spectroscopic study of the
pulsar and PWN independently of each other. The PWN is only evident in the hard
band and consists of jet-like structures extending to at least 7" from the
pulsar, with the southern `jet' being longer than the northern `jet'. The
spectrum of the PWN is described by a power law with a photon index~1.1 for the
compact PWN and ~1.4 for the southern long jet (at a fixed column density of
1.8E22/cm2), and a total luminosity of 4E32 ergs/s (0.5-7 keV), at a distance
of 8.4 kpc. The pulsar's spectrum is clearly softer than the PWN's spectrum. We
rule out a single blackbody model for the pulsar, and present the first
evidence of non-thermal (presumably magnetospheric) emission that dominates
above ~3keV. A two-component model consisting of a power law component (with
photon index ~1.5--2.0) plus a thermal component provides the best fit. The
thermal component can be fit by either a blackbody model with a temperature
kT~0.21 keV, or a neutron star atmospheric model with a temperature kT~0.14
keV. The efficiency of the pulsar in converting its rotational power, Edot,
into non-thermal X-ray emission from the pulsar and PWN is ~5E-4, comparable to
other rotation-powered pulsars with a similar Edot. We discuss our results in
the context of the X-ray manifestation of high-magnetic field radio pulsars in
comparison with rotation-powered pulsars and magnetars.Comment: 26 pages including 3 tables and 7 figures. Accepted for publication
in Ap
Spatial Distribution of Metal Emissions in SNR 3C 397 Viewed with Chandra and XMM
We present X-ray equivalent width imaging of the supernova remnant (SNR) 3C
397 for Mg He\alpha, Si He\alpha, S He\alpha, and Fe K\alpha complex lines with
the Chandra and XMM-Newton observations. The images reveal that the heavier the
element is, the smaller the extent of the element distribution is. The Mg
emission is evidently enhanced in the southeastern blow-out region, well along
the radio boundary there, and appears to partially envelope the eastern Fe
knot. Two bilateral hat-like Si line-emitting structures are along the northern
and southern borders, roughly symmetric with respect to the southeast-northwest
elongation axis. An S line-emitting shell is located just inner to the northern
radio and IR shell, indicating of a layer of reversely shocked sulphur in the
ejecta. A few enhanced Fe features are basically aligned along the diagonal of
the rectangular shape of the SNR, which implicates an early asymmetric SN
explosion.Comment: 4 pages, 4 figures, appears in Science China Physics, Mechanics &
Astronomy, 2010, 53 (Suppl.1), 267-27
- …