The Mopra Southern Galactic Plane CO Survey-data release 4-complete survey

We present observations of the Mopra carbon monoxide (CO) survey of the Southern Galactic Plane, covering Galactic longitudes spanning l = 250◦ (−110◦) to l = 355◦ (−5◦), with a latitudinal coverage of at least |b| 210 deg2. These data have been taken at 0.6 arcmin spatial resolution and 0.1 km s−1 spectral resolution, providing an unprecedented view of the molecular gas clouds of the Southern Galactic Plane in the 109–115 GHz J = 1 − 0 transitions of 12CO, 13CO, C18O, and C17O.K. O. Cubuk ... G. Rowell ... et al

Searching for an interstellar medium association for HESS J1534-571

The Galactic supernova remnant HESSJ1534−571 (also known as G323.7 − 1.0) has a shell-like morphology in TeV gamma-ray emission and is a key object in the study of cosmic ray origin. Little is known about its distance and local environment. We examine Mopra 12CO/13CO(1–0) data, Australian Telescope Compact Array HI⁠, and Parkes HI data towards HESSJ1534−571⁠. We trace molecular clouds in at least five velocity ranges, including clumpy interstellar medium structures near a dip in HI emission at a kinematic velocity consistent with the Scutum–Crux arm at ∼3.5 kpc. This feature may be a cavity blown-out by the progenitor star, a scenario that suggests HESSJ1534−571 resulted from a core-collapse event. By employing parametrizations fitted to a sample of supernova remnants of known distance, we find that the radio continuum brightness of HESSJ1534−571 is consistent with the ∼3.5 kpc kinematic distance of the Scutum–Crux arm HI dip. Modelling of the supernova evolution suggests a ∼8–24 kyr age for HESSJ1534−571 at this distance.Nigel I. Maxted, C. Braiding, G. F. Wong, G. P. Rowell ... Gavin P. Rowell ... Fabien Voisin ... et al

A morphological study of the supernova remnant Rx J0852.0-4622 (Vela Jr.)

We conduct a multiwavelength morphological study of the Galactic supernova remnant (SNR) RX J0852.0–4622 (also known as Vela Jr., Vela Z, and G266.2−1.2). RX J0852.0–4622 is coincident with the edge of the larger Vela SNR causing confusion in the attribution of some filamentary structures to either RX J0852.0–4622 or its larger sibling. We find that the RX J0852.0–4622 radio-continuum emission can be characterized by a two-dimensional shell with a radius of 0fdg90 ± 0fdg01 (or 11.8 ± 0.6 pc at an assumed distance of 750 pc) centered at (l, b) = (133fdg08 ± 0fdg01,−46fdg34 ± 0fdg01) (or R.A. = 8h52m19fs2, decl. = −46°20'24farcs0, J2000), consistent with X-ray and gamma-ray emission. Although [O iii] emission features are generally associated with the Vela SNR, one particular [O iii] emission feature, which we denote as "the Vela Claw," morphologically matches a molecular clump that is thought to have been stripped by the stellar progenitor of the RX J0852.0–4622 SNR. We argue that the Vela Claw feature is possibly associated with RX J0852.0–4622. Toward the northwestern edge of RX J0852.0–4622 , we find a flattening of the radio spectral index toward another molecular clump also thought to be associated with RX J0852.0–4622 . It is currently unclear whether this feature and the Vela Claw result from interactions between the RX J0852.0–4622 shock and interstellar medium gas.Nigel I. Maxted, M. D. Filipović, H. Sano, G. E. Allen, T. G. Pannuti ... T. J. Galvin ... et al

Discovery of a pulsar-powered bow shock nebula in the Small Magellanic Cloud supernova remnant DEMS5

We report the discovery of a new Small Magellanic Cloud pulsar wind nebula (PWN) at the edge of the supernova remnant (SNR) DEM S5. The pulsar powered object has a cometary morphology similar to the Galactic PWN analogues PSR B1951+32 and ‘the mouse’. It is travelling supersonically through the interstellar medium. We estimate the pulsar kick velocity to be in the range of 700–2000 km s−1 for an age between 28 and 10 kyr. The radio spectral index for this SNR–PWN–pulsar system is flat (–0.29 ± 0.01) consistent with other similar objects. We infer that the putative pulsar has a radio spectral index of –1.8, which is typical for Galactic pulsars. We searched for dispersion measures up to 1000 cm−3 pc but found no convincing candidates with an S/N greater than 8. We produce a polarization map for this PWN at 5500 MHz and find a mean fractional polarization of P ∼ 23 per cent. The X-ray power-law spectrum (Γ ∼ 2) is indicative of non-thermal synchrotron emission as is expected from PWN–pulsar system. Finally, we detect DEM S5 in infrared (IR) bands. Our IR photometric measurements strongly indicate the presence of shocked gas that is expected for SNRs. However, it is unusual to detect such IR emission in an SNR with a supersonic bow shock PWN. We also find a low-velocity H i cloud of ∼107 km s−1 that is possibly interacting with DEM S5. SNR DEM S5 is the first confirmed detection of a pulsar-powered bow shock nebula found outside the Galaxy.Rami Z. E. Alsaberi, C. Maitra, M. D. Filipović, L. M. Bozzetto, F. Haberl ... Gavin P Rowell .. et al

A Supernova Remnant Counterpart for HESS J1832-085

We examine the new Galactic supernova remnant (SNR) candidate, G23.11+0.18, as seen by the Murchison Widefield Array radio telescope. We describe the morphology of the candidate and find a spectral index of −0.63 ± 0.05 in the 70–170 MHz domain. Coincident TeV gamma-ray detection in High Energy Stereoscopic System (HESS) data supports the SNR nature of G23.11+0.18 and suggests that G23.11+0.18 is accelerating particles beyond TeV energies, thus making this object a promising new cosmic-ray hadron source candidate. The remnant cannot be seen in current optical, infrared and X-ray data sets. We do find, however, a dip in CO-traced molecular gas at a line-of-sight velocity of ~85 km s−1, suggesting the existence of a G23.11+0.18 progenitor wind-blown bubble. Furthermore, the discovery of molecular gas clumps at a neighboring velocity toward HESS J1832−085 adheres to the notion that a hadronic gamma-ray production mechanism is plausible toward the north of the remnant. Based on these morphological arguments, we propose an interstellar medium association for G23.11+0.18 at a kinematic distance of 4.6 ± 0.8 kpc.Nigel I. Maxted, M. D. Filipović, N. Hurley-Walker, I. Bojičić, G. P. Rowell, F. Haberl ... et al

The Mopra Southern Galactic Plane CO Survey - Data release 4 - Complete survey

We present observations of the Mopra carbon monoxide (CO) survey of the Southern Galactic Plane, covering Galactic longitudes spanning to , with a latitudinal coverage of at least 210 deg, totalling an area of $. These data have been taken at 0.6 arcmin spatial resolution and 0.1 km s spectral resolution, providing an unprecedented view of the molecular gas clouds of the Southern Galactic Plane in the 109-115 GHz transitions of CO, CO, C O, and C O