scholarly journals Optical Identification and Spectroscopy of Supernova Remnants in the Galaxy M51

2021 ◽  
Vol 908 (1) ◽  
pp. 80
Author(s):  
P. Frank Winkler ◽  
Sadie C. Coffin ◽  
William P. Blair ◽  
Knox S. Long ◽  
Kip D. Kuntz
1998 ◽  
Vol 179 ◽  
pp. 103-105
Author(s):  
S.A. Trushkin

Now in radio continuum surveys more than 10,000 radio sources have discovered in the Milky Way plane but the Galactic origin only of a small part of them has been determined. The problem comes from the absence of estimates of source distance and the optical identification even for bright radio sources, and the most of sources have not spectral data at 2-3 frequencies. As followed some hundreds of sources have not classified as thermal or non-thermal. Now we don't know the full number of supernova remnants (SNRs) in the Galaxy. The simple estimates show that a sample of Galactic SNRs is not full as for weak and extended (> 15′) as for bright and compact (< 3′) SNRs (Trushkin 1993).


1975 ◽  
Vol 67 ◽  
pp. 501-508
Author(s):  
P. R. Amnuel ◽  
O. H. Guseinov

In order to find out the physical nature of galactic X-ray sources, data on the variability of 24 sources during 1964–1971 have been investigated. The fluxes of 9 sources are found to be increasing to the maximum value (for several months) and then slowly decreasing (for 3 years). These 9 sources have been related by us to the class of X-ray Novae. The X-ray Nova synthetic light curve has been drawn from data of the fluxes of 9 discovered Novae. Assumptions have been made on the physical nature of the X-ray Novae. Between the flares the X-ray Novae may be weak X-ray sources with a luminosity of about 1034 erg s−1. During the flares the luminosity increases to about 1038 erg s−1. The number of X-ray sources in the Galaxy is about 103–104. The object of the optical identification may be a dwarf star of no earlier spectral class than F.


1988 ◽  
Vol 101 ◽  
pp. 363-378 ◽  
Author(s):  
Eli Dwek

AbstractInfrared observations of supernova remnants obtained with the Infrared Astronomical Satellite provide new insights into the dynamics and energetics of the remnants, and into their interaction with the ambient interstellar medium. In most remnants the infrared emission arises from dust that is collisionally heated by the X-ray emitting gas. The infrared observations can therefore be used as a diagnostic for the physical conditions of the shocked gas. In particular, it is shown that all the prominent X-ray remnants in the Galaxy and in the LMC cool mainly by dust grain collisions instead of atomic processes.


1979 ◽  
Vol 84 ◽  
pp. 119-123
Author(s):  
Joseph H. Taylor

Recent pulsar surveys have increased the number of known pulsars to well over 300, and many of them lie at distances of several kpc or more from the sun. The distribution of pulsars with respect to distance from the galactic center is similar to other population I material such as HII regions, supernova remnants, and carbon monoxide gas, but the disk thickness of the pulsar distribution is rather greater, with <|z|>≈350 pc. Statistical analysis suggests that the total number of active pulsars in the Galaxy is a half million or more, and because kinematic arguments require the active lifetimes of pulsars to be ≲5×106 years, it follows that the birthrate required to maintain the observed population is one pulsar every ∼10 years (or less) in the Galaxy.


2008 ◽  
Author(s):  
Luke O’C. Drury ◽  
Gang Li ◽  
Qiang Hu ◽  
Olga Verkhoglyadova ◽  
Gary P. Zank ◽  
...  

2019 ◽  
Vol 490 (3) ◽  
pp. 4317-4333 ◽  
Author(s):  
S Celli ◽  
G Morlino ◽  
S Gabici ◽  
F A Aharonian

ABSTRACT The escape process of particles accelerated at supernova remnant (SNR) shocks is one of the poorly understood aspects of the shock acceleration theory. Here we adopt a phenomenological approach to study the particle escape and its impact on the gamma-ray spectrum resulting from hadronic collisions both inside and outside of a middle-aged SNR. Under the assumption that in the spatial region immediately outside of the remnant the diffusion coefficient is suppressed with respect to the average Galactic one, we show that a significant fraction of particles are still located inside the SNR long time after their nominal release from the acceleration region. This fact results into a gamma-ray spectrum that resembles a broken power law, similar to those observed in several middle-aged SNRs. Above the break, the spectral steepening is determined by the diffusion coefficient outside of the SNR and by the time dependence of maximum energy. Consequently, the comparison between the model prediction and actual data will contribute to determining these two quantities, the former being particularly relevant within the predictions of the gamma-ray emission from the halo of escaping particles around SNRs, which could be detected with future Cherenkov telescope facilities. We also calculate the spectrum of runaway particles injected into the Galaxy by an individual remnant. Assuming that the acceleration stops before the SNR enters the snowplow phase, we show that the released spectrum can be a featureless power law only if the accelerated spectrum is ∝ p−α with α > 4.


1987 ◽  
Vol 125 ◽  
pp. 23-33
Author(s):  
A.G. Lyne

Pulsars have a galactic radial distribution similar to that of many galactic populations such as HII regions, massive stars and supernova remnants. However they are generally much further from the plane of the Galaxy than these objects. Proper motion measurements sho that this is because they are typically moving with high velocities. The measurements also indicate that most pulsars were formed a few million years ago close to the plane, within the normal Population I regions. Some pulsars will escape from the Galaxy, although the majority will end up in a halo population. The origin of the high velocities is not clear at present but may be due either to some asymme try in the formation event or to the disruption of a close binary system.


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