scholarly journals Optical Observations of four Balmer-Dominated Supernova Remnants in the Large Magellanic Cloud

1983 ◽  
Vol 101 ◽  
pp. 559-565
Author(s):  
I. R. Tuohy ◽  
M. A. Dopita ◽  
D. S. Mathewson ◽  
K. S. Long ◽  
D. J. Helfand

We report the optical identification of four Balmer-dominated supernova remnants (SNRs) in the Large Magellanic Cloud. Both the Balmer-dominated spectra and the presence of a broad Hα component in one remnant can be understood in terms of a very high velocity non-radiative shock encountering gas which is partially neutral, as proposed originally by Chevalier and Raymond to account for the similar spectra of the galactic remnants, Tycho and SN1006. From a consideration of the optical and X-ray luminosities of the SNR with broad Hα emission, we infer that the fraction of neutral gas in the medium is ≲ 30%. Radio observations of the LMC remnants show that their surface brightnesses are anomalously low; this could be intrinsic to the supernova themselves, or a result of their environment. Finally, we argue that the four SNRs all resulted from Type I supernovae, in which case they are the first such remnants to be identified outside the Galaxy.

1998 ◽  
Vol 115 (3) ◽  
pp. 1057-1075 ◽  
Author(s):  
John R. Dickel ◽  
D. K. Milne

2020 ◽  
Vol 500 (2) ◽  
pp. 2336-2358
Author(s):  
Miranda Yew ◽  
Miroslav D Filipović ◽  
Milorad Stupar ◽  
Sean D Points ◽  
Manami Sasaki ◽  
...  

ABSTRACT We present a new optical sample of three Supernova Remnants (SNRs) and 16 Supernova Remnant (SNR) candidates in the Large Magellanic Cloud (LMC). These objects were originally selected using deep H α, [S ii], and [O iii] narrow-band imaging. Most of the newly found objects are located in less dense regions, near or around the edges of the LMC’s main body. Together with previously suggested MCSNR J0541–6659, we confirm the SNR nature for two additional new objects: MCSNR J0522–6740 and MCSNR J0542–7104. Spectroscopic follow-up observations for 12 of the LMC objects confirm high [S ii]/H α emission-line ratios ranging from 0.5 to 1.1. We consider the candidate J0509–6402 to be a special example of the remnant of a possible type Ia Supernova (SN) which is situated some 2° (∼1.75 kpc) north from the main body of the LMC. We also find that the SNR candidates in our sample are significantly larger in size than the currently known LMC SNRs by a factor of ∼2. This could potentially imply that we are discovering a previously unknown but predicted, older class of large LMC SNRs that are only visible optically. Finally, we suggest that most of these LMC SNRs are residing in a very rarefied environment towards the end of their evolutionary span where they become less visible to radio and X-ray telescopes.


1998 ◽  
Vol 15 (1) ◽  
pp. 128-131 ◽  
Author(s):  
Miroslav D. Filipović ◽  
Paul A. Jones ◽  
Graeme L. White ◽  
Raymond F. Haynes

AbstractWe present a comparison between the latest Parkes radio surveys (Filipović et al. 1995, 1996, 1997) and Hα surveys of the Magellanic Clouds (Kennicutt & Hodge 1986). We have found 180 discrete sources in common for the Large Magellanic Cloud (LMC) and 40 in the field of the Small Magellanic Cloud (SMC). Most of these sources (95%) are HII regions and supernova remnants (SNRs). A comparison of the radio and Hα flux densities shows a very good correlation and we note that many of the Magellanic Clouds SNRs are embedded in HII regions.


2016 ◽  
Vol 586 ◽  
pp. A4 ◽  
Author(s):  
P. J. Kavanagh ◽  
M. Sasaki ◽  
L. M. Bozzetto ◽  
S. D. Points ◽  
E. J. Crawford ◽  
...  

1991 ◽  
Vol 148 ◽  
pp. 161-164 ◽  
Author(s):  
S. van den Bergh

Star clusters in the Magellanic Clouds (MCs) differ from those in the Galaxy in a number of respects: (1) the Clouds contain a class of populous open clusters that has no Galactic counterpart; (2) Cloud clusters have systematically larger radii rh than those in the Galaxy; (3) clusters of all ages in the Clouds are, on average, more flattened than those in the Galaxy. In the Large Magellanic Cloud (LMC) there appear to have been two distinct epochs of cluster formation. LMC globulars have ages of 12-15 Gyr, whereas most populous open clusters have ages <5 Gyr. No such dichotomy is observed for clusters in the Small Magellanic Cloud (SMC) The fact that the SMC exhibits no enhanced cluster formation at times of bursts of cluster formation in the LMC, militates against encounters between the Clouds as a cause for enhanced rates of star and cluster formation.


2008 ◽  
pp. 61-66 ◽  
Author(s):  
E.J. Crawford ◽  
M.D. Filipovic ◽  
Horta de ◽  
F.H. Stootman ◽  
J.L. Payne

We present the results of new moderate resolution ATCA observations of SNR J0455-6838. We found that this SNR exhibits a mostly typical appearance with rather steep and curved ?=-0.81?0.18 and D=43?31?1 pc. Regions of high polarization were detected, including unusually strong (~70%) region corresponding to the northern breakout. Such a strong polarization in breakout regions has not been observed in any other SNR.


1988 ◽  
Vol 100 ◽  
pp. 683 ◽  
Author(s):  
Tony A. Forest ◽  
David L. Spenny ◽  
Roger W. Johnson

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