Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userNew high-resolution radio observations of the SNR CTB 80
181
0
0.0
(
0
)
Authors
G. Castelleti
Ask ChatGPT about the research
No Arabic abstract
We report new high resolution and high sensitivity radio observations of the extended supernova remnant (SNR) CTB 80 (G69.0+2.7) at 240 MHz, 324 MHz, 618 MHz, and 1380 MHz. The imaging of CTB 80 at 240 MHz and 618 MHz was performed using the Giant Metrewave Radio Telescope (GMRT) in India. The observations at 324 MHz and 1380 MHz were obtained using the Very Large Array (VLA, NRAO) in its C and D configurations. The new radio images reveal faint extensions for the asymmetric arms of CTB 80. The arms are irregular with filaments and clumps of size 1 (or 0.6 pc at a distance of 2 kpc). The radio image at 1380 MHz is compared with IR and optical emission. The correspondence IR/radio is excellent along the N arm of CTB 80. Ionized gas observed in the [SII] line perfectly matches the W and N edges of CTB 80. The central nebula associated with the pulsar PSR B1951+32 was investigated with an angular resolution of 10 x 6. The new radio image obtained at 618 MHz shows with superb detail structures in the 8 x 4 E-W ``plateau nebula that hosts the pulsar on its western extreme. A twisted filament, about 6 in extent (~3.5 pc), trails behind the pulsar in an approximate W-E direction. In the bright ``core nebula (size ~45), located to the W of the plateau, the images show a distortion in the morphology towards the W; this feature corresponds to the direction in which the pulsar escapes from the SNR with a velocity of ~240 km/s. Based on the new observations, the energetics of the SNR and of the PWN are investigated.
rate research
Read More
We investigated the kinematics of the pulsar wind nebula (PWN) associated with PSR B1951+32 in the old supernova remnant CTB 80 using the Fabry-Perot interferometer of the 6m Special Astrophysical Observatory telescope. In addition to the previously known expansion of the system of bright filaments with a velocity of 100-200km/s, we detected weak high-velocity features in the H-alpha line at least up to velocities of 400-450km/s. We analyzed the morphology of the PWN in the H-alpha, [SII], and [OIII] lines using HST data and discuss its nature. The shape of the central filamentary shell, which is determined by the emission in the [OIII] line and in the radio continuum, is shown to be consistent with the bow-shock model for a significant (about 60 degrees) inclination of the pulsars velocity vector to the plane of the sky. In this case, the space velocity of the pulsar is twice higher than its tangential velocity, i.e., it reaches ~500 km/s, and PSR B1951+32 is the first pulsar whose line-of-sight velocity (of about 400 km/s) has been estimated from the PWN observations. The shell-like H-alpha-structures outside the bow shock front in the east and the west may be associated with both the pulsars jets and the pulsar-wind breakthrough due to the layered structure of the extended CTB 80 shell.
We present a radio polarization study of the supernova remnant CTB 80 based on images at 1420 MHz from the Canadian Galactic plane survey, at 2695 MHz from the Effelsberg survey of the Galactic plane, and at 4800 MHz from the Sino-German 6cm polarization survey of the Galactic plane. We obtained a rotation measure (RM) map using polarization angles at 2695 MHz and 4800 MHz as the polarization percentages are similar at these two frequencies. RM exhibits a transition from positive values to negative values along one of the shells hosting the pulsar PSR B1951+32 and its pulsar wind nebula. The reason for the change of sign remains unclear. We identified a partial shell structure, which is bright in polarized intensity but weak in total intensity. This structure could be part of CTB 80 or part of a new supernova remnant unrelated to CTB 80.
We present direct images in the H$alpha$ and [SII]$lambda lambda$6717,6731 $text{AA}$ lines of the Galactic Supernova Remnant G109.1-1.0 (CTB 109). We confirm that the filaments detected are the optical counterpart of the X-ray and radio supernova remnant due to their high [SII]/H$alpha$ line-ratios. We study for the first time the kinematics of the optical counterpart of SNR CTB 109 using the UNAM scanning Fabry-Perot interferometer PUMA. We estimate a systemic velocity of V$_{LSR}$=-50$pm$6 km s$^{-1}$ for this remnant and an expansion velocity of V$_{exp}$=230$pm$5 km s$^{-1}$. From this velocity value and taking into account previous studies about the kinematics of objects at that Galactic longitude we derive a distance to the SNR CTB 109 of 3.1$pm$0.2 kpc, locating it in the Perseus arm. Using the [SII]$lambda$6717/[SII]$lambda$6731 line-ratio we find an electronic density value around n$_e$= 580 cm$^{-3}$. Considering that this remnant is evolving in a low density medium with higher density cloudlets responsible of the optical emission, we determine the age and energy deposited in the ISM by the supernova explosion (E$_0$) in both the Sedov-Taylor phase and the radiative phase. For both cases the age is of thousands of years and the E$_0$ is rather typical of SNRs containing simple pulsars so that, the energy released to the ISM cannot be used to distinguish between supernova remnants hosting typical pulsars from those hosting powerful magnetars as in the case of CTB 109.
We have produced sensitive, high-resolution radio maps of 12 SMGs in the Lockman Hole using combined MERLIN and VLA data at a frequency of 1.4 GHz. Integrating for 350hr yielded an r.m.s. noise of 6.0 uJy/beam and a resolution of 0.2-0.5. For the first time, wide-field data from the two arrays have been combined in the (u,v) plane and the bandwidth smearing response of the VLA data has been removed. All of the SMGs are detected in our maps as well as sources comprising a non-submm luminous control sample. We find evidence that SMGs are more extended than the general uJy radio population and that therefore, unlike in local ULIRGs, the starburst component of the radio emission is extended and not confined to the galactic nucleus. For the eight sources with redshifts we measure linear sizes between 1 and 8 kpc with a median of 5 kpc. Therefore, they are in general larger than local ULIRGs which may support an early-stage merger scenario for the starburst trigger. X-rays betray AGN in six of the 33 sources in the combined sample. All but one of these are in the control sample, suggesting a lower incidence of AGN amongst the submm-luminous galaxies which is, in turn, consistent with increased X-ray absorption in these dust-obscured starbursts. Only one of our sources is resolved into multiple, distinct components with our high-resolution data. Finally, compared to a previous study of faint radio sources in the GOODS-N field we find systematically smaller source sizes and no evidence for a tail extending to ~4. Possible reasons for this are discussed.
We report on new Australia Telescope Compact Array (ATCA) observations of the Large Magellanic Cloud (LMC) supernova remnant (SNR) J0550-6823 (DEM L328). This object is a typical horseshoe SNR with a diameter of 373 x 282 +- 4 (90 x 68 +- 1), making it one of the largest known SNRs in the Local Group. We estimate a relatively steep radio spectral index of alpha = -0.79 +- 0.27. However, its stronger than expected polarisation of 50% +- 10% is atypical for older and more evolved SNRs. We also note a strong correlation between [Oiii] and radio images, classifying this SNR as oxygen dominant.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
