25,876 research outputs found
The HI absorption distance of HESS J1943+213 favours its extragalactic nature
The H.E.S.S. collaboration (Abramowski et al. 2011) dicovered a new TeV
point-like source HESS J1943+213 in the Galactic plane and suggested three
possible low-energy-band counterparts: a -ray binary, a pulsar wind
nebula (PWN), or a BL Lacertae object. We measure the distance to the radio
counterpart G57.76-1.29 of HESS J1943+213. We analyze Very Large Array
observations to obtain a reliable HI absorption spectrum.The resulting distance
limit is 16 kpc. This distance strongly supports that HESS J1943+213 is
an extragalactic source, consistent with the preferred counterpart of the HESS
collaboration.Comment: 3 figures, 2 pages, A&A accepte
Discovery of A New Faint Radio SNR G108.2-0.6
A new faint and large shell-type radio Supernova Remnant (SNR) G108.2-0.6 has
been discovered in the Canadian Galactic Plane Survey (CGPS). The SNR shows an
elliptical shell-type structure at 1420 MHz, and has a 408-1420 MHz TT-plot
spectral index of =-0.50.1 (S),
typical of a shell-type SNR. The remnant's flux density at 1420 MHz is
6.60.7 Jy, and at 408 MHz is 11.51.2 Jy. Both of these are corrected
for compact sources. An integrated spectral index of 0.13 is
determined. This new SNR has among the lowest surface brightness of any known
remnant (=2.4 W m Hz
sr). 21 cm Stokes Q and U CGPS data (plus preliminary Effelsberg Q and U
maps) show some suggestive features that correlate with total power. \ion{H}{i}
observations show structures associated with G108.20.6 in the radial
velocity range 53 to 58 km s, and indicate it is located in the
Perseus arm shock at a distance of 3.20.6 kpc. At this distance the
diameter of G108.20.6 is 58 pc. IRAS maps (12, 25, 60 and 100\mu m) of the
new SNR show rich infrared emission surrounding G108.20.6.Comment: 10 pages, 6 figs, accepted by A&
The Distance and Age of the SNR Kes 73 and AXP 1E 1841-045
We provide a new distance estimate to the supernova remnant (SNR) Kes 73 and
its associated anomalous X-ray pulsar (AXP) 1E 1841-045. 21 cm HI images and HI
absorption/ emission spectra from new VLA observations, and 13CO emission
spectra of Kes 73 and two adjacent compact HII regions (G27.276+0.148 and
G27.491+0.189) are analyzed. The HI images show prominent absorption features
associated with Kes 73 and the HII regions. The absorption appears up to the
tangent point velocity giving a lower distance limit to Kes 73 of 7.5 kpc,
which has previously been given as the upper limit. Also, G27.276+0.148 and
G27.491+0.189 are at the far kinematic distances of their radio recombination
line velocities. There is prominent HI emission in the range 80--90 km/s for
all three objects. The two HII regions show HI absorption at ~ 84 km/s, but
there is no absorption in the Kes 73 absorption spectrum. This implies an upper
distance limit of ~ 9.8 kpc to Kes 73. This corrected larger distance to Kes
73/ AXP 1E 1841-045 system leads to a refined age of the SNR of 500 to 1000 yr,
and a ~ 50% larger AXP X-ray luminosity.Comment: 10 pages, 2 figures, ApJ, dol:10.1086/"529120
The radio SNR G65.1+0.6 and its associated pulsar J1957+2831
New images of the radio Supernova Remnant (SNR) G65.1+0.6 are presented,
based on the 408 MHz and 1420 MHz continuum emission and the HI-line emission
data of the Canadian Galactic Plane Survey (CGPS). A large shell-like structure
seen in the 2695 MHz Effelsberg map appears to have nonthermal spectral index.
HI observations show structures associated with the SNR G65.1+0.6 in the radial
velocity range of -20 to -26 kms and suggest a distance of 9.2 kpc for the
SNR. The estimated Sedov age for G65.1+0.6 is 4 - 14 x10E4 yr. The pulsar (PSR)
J1957+2831 is possibly associated with G65.1+0.6, with consistent distance and
kinematic age estimate, but different characteristic age than the SNR. The
EGRET source 3EG J1958+2909 and gamma-ray source 2CG 065+00 are also near the
eastern edge of the SNR but do not agree in position with the pulsar and are
likely not associated with the SNR. The SNR's flux densities at 408 MHz
(8.6+-0.8 Jy), 1420 MHz (4.9+-0.5 Jy) and 2695 MHz (3.3+-0.5 Jy) have been
corrected for flux densities from compact sources within the SNR. The
integrated flux density based spectral index between 1420 MHz and 408 MHz is
0.45+-0.11 and agrees with the T-T plot spectral index of 0.34+-0.20. The
nearby SNR DA495 has a T-T plot spectral index of 0.50+-0.01.Comment: 7pages, 5 pictures and tables, will appear in A&
Using interference for high fidelity quantum state transfer in optomechanics
We revisit the problem of using a mechanical resonator to perform the
transfer of a quantum state between two electromagnetic cavities (e.g. optical
and microwave). We show that this system possesses an effective mechanical dark
state which is immune to mechanical dissipation; utilizing this feature allows
highly efficient transfer of intra-cavity states, as well as of itinerant
photon states. We provide simple analytic expressions for the fidelity of
transferring both Gaussian and non-Gaussian states.Comment: 5 pages, 2 figure
Classification of All Poisson-Lie Structures on an Infinite-Dimensional Jet Group
A local classification of all Poisson-Lie structures on an
infinite-dimensional group of formal power series is given. All
Lie bialgebra structures on the Lie algebra {\Cal G}_{\infty} of
are also classified.Comment: 11 pages, AmSTeX fil
Distance to the SNR CTB 109/AXP 1E 2259+586 by HI absorption and self-absorption
We suggest a revised distance to the supernova remnant (SNR) G109.1-1.0 (CTB
109) and its associated anomalous X-ray pulsar (AXP) 1E 2259+586 by analyzing
21cm HI-line and 12CO-line spectra of CTB 109, HII region Sh 152, and the
adjacent molecular cloud complex. CTB 109 has been established to be
interacting with a large molecular cloud (recession velocity at v=-55 km s^-1).
The highest radial velocities of absorption features towards CTB 109 (-56 km
s^-1) and Sh 152 (-65 km s^-1) are larger than the recombination line velocity
(-50 km s^-1) of Sh 152 demonstrating the velocity reversal within the Perseus
arm. The molecular cloud has cold HI column density large enough to produce HI
self-absorption (HISA) and HI narrow self-absorption (HINSA) if it was at the
near side of the velocity reversal. Absence of both HISA and HINSA indicates
that the cloud is at the far side of the velocity reversal within the Perseus
Arm, so we obtain a distance for CTB 109 of 4+/-0.8 kpc. The new distance still
leads to a normal explosion energy for CTB 109/AXP 1E 2259+586.Comment: 5 pages, 3 figures. Accepted by MNRAS Letter
The Distances of SNRs Kes 69 and G21.5-0.9 from HI and 13CO Spectra
We obtain new HI and CO images around Supernova Remnants (SNR) Kes 69
and G21.5-0.9. By comparing HI spectra with CO emission spectra, we
significantly revise the kinematic distance for Kes 69 to 5.5 kpc, which
was 11.2 kpc, and refine the kinematic distance for G21.5-0.9 to ~4.8 kpc. For
Kes 69, the highest velocity of absorption is ~86 km/s and a prominent HI
emission feature at ~ 112 km/s has no respective absorption. These new results
suggest that Kes 69 is associated with a newly detected extended 1720 MHz OH
maser at velocity of ~85 km/s that originates from within the bright southern
radio shell of Kes 69. For G21.5-0.9, the highest velocity of absorption is ~67
km/s. The HI absorption spectra of the nearby bright source PMN J1832-1035 and
of Kes 69 show a common absorption feature at velocity of ~69 km/s, which is
not seen for G21.5-0.9. The resulting velocity of ~68 km/s gives the best
distance estimate of ~4.8 kpc for G21.5-0.9 and associated young pulsar
J1833-1034.Comment: 5 page, 2 figs. Monthly Notices of the Royal Astronomical Society:
Letters. in pres
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