ALMA CO Observations of Gamma-Ray Supernova Remnant N132D in the Large Magellanic Cloud: Possible Evidence for Shocked Molecular Clouds Illuminated by Cosmic-Ray Protons

The Large Magellanic Cloud (LMC) is a spiral galaxy, satellite of the Milky way with a high star formation activity. It represents a unique laboratory for studying an extended and spatially resolved star-forming galaxy through gamma-ray observatories. Therefore, the LMC survey is one of the key science projects for the Cherenkov Telescope Array (CTA), the next-generation ground-based gamma-ray observatory. In this document we present the work performed over the last year by the CTA working group dedicated to the LMC, in order to offer a first characterization of the LMC at TeV energies. We have performed detectability forecasts based on the expected CTA performance for all sources in the region of interest of the LMC with known emission at GeV energies and above. Based on previous observations made by Fermi-LAT and H.E.S.S. we have characterized all point sources, extended sources and diffuse emission produced by cosmic-ray propagation, extrapolating their spectra to CTA energies. Finally, we have characterized the signal expected by different annihilation mechanisms of dark matter (DM) particles within the LMC, computing the detection sensitivity curve for this target in the cross-section-to-mass plane.

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Cosmic Rays and the Dynamic Balance in the Large Magellanic Cloud

International Astronomical Union Colloquium ◽

10.1017/s0252921100077630 ◽

1990 ◽

Vol 123 ◽

pp. 537-541

Author(s):

Carl E. Fichtel ◽

Mehmet E. Ozel ◽

Robert G. Stone

Keyword(s):

Cosmic Rays ◽

Gamma Ray ◽

Dynamic Balance ◽

Cosmic Ray ◽

Large Magellanic Cloud ◽

High Energy ◽

Magellanic Cloud ◽

Density Level ◽

Energy Gamma ◽

Galactic Dynamic

AbstractPresent and future measurement of the Large Magellanic Cloud (LMC) particularly in the radio and high energy gamma ray range offer the possibility of understanding the density and distribution of the cosmic rays in a galaxy other than our own and the role that they play in galactic dynamic balance. After a study of the consistency of the measurements and interpretation of the synchrotron radiation from our own galaxy, the cosmic ray distribution for the LMC is calculated under the assumption that the cosmic ray nucleon to electron ratio is the same and the relation to the magnetic fields are the same, although the implications of alternatives are discussed. It is seen that the cosmic ray density level appears to be similar to that in our own galaxy, but varying in position in a manner generally consistent with the concept of correlation with the matter on a broad scale.

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AN X-RAY STUDY OF SUPERNOVA REMNANT N49 AND SOFT GAMMA-RAY REPEATER 0526-66 IN THE LARGE MAGELLANIC CLOUD

The Astrophysical Journal ◽

10.1088/0004-637x/748/2/117 ◽

2012 ◽

Vol 748 (2) ◽

pp. 117 ◽

Cited By ~ 40

Author(s):

Sangwook Park ◽

John P. Hughes ◽

Patrick O. Slane ◽

David N. Burrows ◽

Jae-Joon Lee ◽

...

Keyword(s):

Supernova Remnant ◽

Gamma Ray ◽

Large Magellanic Cloud ◽

Magellanic Cloud ◽

X Ray

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The Environment of Tycho: Possible Interaction with Molecular Clouds

Symposium - International Astronomical Union ◽

10.1017/s0074180900180611 ◽

2004 ◽

Vol 218 ◽

pp. 71-72

Author(s):

Jae-Joon Lee ◽

Bon-Chul Koo ◽

Keni'chi Tatemastu

Keyword(s):

High Resolution ◽

Molecular Cloud ◽

Molecular Clouds ◽

Supernova Remnant ◽

Cosmic Ray ◽

Perseus Arm ◽

Tycho’S Snr ◽

Co Observations

We have conducted 12CO observations with the Nobeyama 45-m telescope in the area of Tycho's supernova remnant. These high-resolution (16″) data show that the molecular cloud surrounds the SNR along the northeastern boundary. We suggest that Tycho's SNR and the molecular cloud are located at comparable distances within the Perseus arm and that they are physically interacting. We also discuss the possible connection between the molecular cloud and the Balmer-dominated optical filaments and propose that the preshock gas may be accelerated within the cosmic-ray and/or fast neutral precursor.

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Constraining the cosmic ray spectrum in the vicinity of the supernova remnant W28: from sub-GeV to multi-TeV energies

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936927 ◽

2020 ◽

Vol 635 ◽

pp. A40

Author(s):

V. H. M. Phan ◽

S. Gabici ◽

G. Morlino ◽

R. Terrier ◽

J. Vink ◽

...

Keyword(s):

Cosmic Rays ◽

Molecular Clouds ◽

Supernova Remnants ◽

Supernova Remnant ◽

Gamma Ray ◽

Cosmic Ray ◽

Ionization Rate ◽

High Energy ◽

Radio Waves ◽

X Ray

Context. Supernova remnants interacting with molecular clouds are ideal laboratories to study the acceleration of particles at shock waves and their transport and interactions in the surrounding interstellar medium. Aims. Here, we focus on the supernova remnant W28, which over the years has been observed in all energy domains from radio waves to very-high-energy gamma rays. The bright gamma-ray emission detected from molecular clouds located in its vicinity revealed the presence of accelerated GeV and TeV particles in the region. An enhanced ionization rate has also been measured by means of millimeter observations, but such observations alone cannot tell us whether the enhancement is due to low-energy (MeV) cosmic rays (either protons or electrons) or the X-ray photons emitted by the shocked gas. The goal of this study is to determine the origin of the enhanced ionization rate and to infer from multiwavelength observations the spectrum of cosmic rays accelerated at the supernova remnant shock in an unprecedented range spanning from MeV to multi-TeV particle energies. Methods. We developed a model to describe the transport of X-ray photons into the molecular cloud, and we fitted the radio, millimeter, and gamma-ray data to derive the spectrum of the radiating particles. Results. The contribution from X-ray photons to the enhanced ionization rate is negligible, and therefore the ionization must be due to cosmic rays. Even though we cannot exclude a contribution to the ionization rate coming from cosmic-ray electrons, we show that a scenario where cosmic-ray protons explain both the gamma-ray flux and the enhanced ionization rate provides the most natural fit to multiwavelength data. This strongly suggests that the intensity of CR protons is enhanced in the region for particle energies in a very broad range covering almost six orders of magnitude: from ≲100 MeV up to several tens of TeV.

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Molecules in the Magellanic Clouds

Symposium - International Astronomical Union ◽

10.1017/s0074180900201046 ◽

1991 ◽

Vol 148 ◽

pp. 415-420 ◽

Cited By ~ 1

Author(s):

R. S. Booth ◽

Th. De Graauw

Keyword(s):

High Resolution ◽

Molecular Clouds ◽

Short Review ◽

Large Magellanic Cloud ◽

Magellanic Cloud ◽

Magellanic Clouds ◽

Giant Molecular Clouds ◽

Interstellar Molecules ◽

First Time ◽

Excitation Conditions

In this short review we describe recent new observations of millimetre transitions of molecules in selected regions of the Magellanic Clouds. The observations were made using the Swedish-ESO Submillimetre Telescope, SEST, (Booth et al. 1989), the relatively high resolution of which facilitates, for the first time, observations of individual giant molecular clouds in the Magellanic Clouds. We have mapped the distribution of the emission from the two lowest rotational transitions of 12CO and 13CO and hence have derived excitation conditions for the molecule. In addition, we have observed several well-known interstellar molecules in the same regions, thus doubling the number of known molecules in the Large Magellanic Cloud (LMC). The fact that all the observations have been made under controlled conditions with the same telescope enables a reasonable intercomparison of the molecular column densities. In particular, we are able to observe the relative abundances among the different isotopically substituted species of CO.

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New optically identified supernova remnants in the Large Magellanic Cloud

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3382 ◽

2020 ◽

Vol 500 (2) ◽

pp. 2336-2358

Author(s):

Miranda Yew ◽

Miroslav D Filipović ◽

Milorad Stupar ◽

Sean D Points ◽

Manami Sasaki ◽

...

Keyword(s):

Supernova Remnants ◽

Supernova Remnant ◽

Narrow Band Imaging ◽

Large Magellanic Cloud ◽

Magellanic Cloud ◽

Main Body ◽

Found Objects ◽

Type Ia ◽

Optical Sample

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.

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