scholarly journals Kinematics of Supernova Remnants in the Galaxy and LMC

1983 ◽  
Vol 101 ◽  
pp. 295-298
Author(s):  
Peter Shull
Keyword(s):  
Supernova Remnants ◽  
Spectral Feature ◽  
Optical Emission ◽  
Emission Lines ◽  
Cygnus Loop ◽  
Interstellar Media ◽  
The Galaxy ◽  
Very High

The optical emission lines of six SNRs have been observed at very high angular and kinematic resolutions. Kinematic ion temperatures were derived, and evidence was found in shocked regions for Maxwellian microturbulence on scales ≤ 0.01 pc, and for non-Maxwellian macroturbulence on scales > 0.1 pc. The widths of shocked regions in the Cygnus Loop and the existence of three types of spectral feature in the LMC remnants are discussed in terms of SNR evolution in cloudy interstellar media.

scholarly journals Absorption and Production of Soft X-Rays in the Galaxy

1973 ◽  
Vol 55 ◽  
pp. 235-249
Author(s):  
S. Hayakawa
Keyword(s):  
Emission Lines ◽  
Interstellar Matter ◽  
X Rays ◽  
Diffuse Component ◽  
Number Density ◽  
High Number Density ◽  
Hard Component ◽  
X Ray ◽  
Cygnus Loop ◽  
The Galaxy

The column densities of interstellar hydrogen to X-ray sources derived from their spectra are compared with those obtained from 21 cm radio observations. Referring to several observed results on Cyg X-2, Cygnus Loop etc., the interpretation of the low energy cut-off of the spectrum in terms of the interstellar absorption is subject to ambiguities due to a modification of the emission spectrum by Compton scattering in the sources and the contribution of emission lines.The result of soft X-ray sky surveys indicates that the diffuse component of soft X-rays consists of the extragalactic and the galactic components. The former has a hard component with a power law spectrum and a soft component which may be represented by an exponential spectrum. The galactic component is so soft that its spectrum may also be explained by thermal bremsstrahlung of temperature of about 0.1 keV. Its generation rate may account for the heating and ionization of interstellar matter. It is suggested that galactic diffuse soft X-rays are produced by active stars of a rather high number density.

scholarly journals The Wisconsin Hα Mapper (WHAM): A Brief Review of Performance Characteristics and Early Scientific Results

1998 ◽  
Vol 15 (1) ◽  
pp. 14-18 ◽  
Author(s):  
R. J. Reynolds ◽  
S. L. Tufte ◽  
L. M. Haffner ◽  
K. Jaehnig ◽  
J. W. Percival
Keyword(s):  
High Velocity ◽  
Optical Emission ◽  
Emission Lines ◽  
Spectral Window ◽  
Sky Surveys ◽  
Early Results ◽  
Fabry Perot ◽  
The Galaxy ◽  
High Velocity Clouds ◽  
Scientific Results

Abstract. The Wisconsin Hα Mapper (WHAM) is a recently completed facility for the detection and study of faint optical emission lines from diffuse ionised gas in the disk and halo of the Galaxy. WHAM consists of a 15 cm diameter Fabry–Perot spectrometer coupled to a 0·6 m ‘telescope’, which provide a 1° diameter beam on the sky and produce a 12 km s−1 resolution spectrum within a 200 km s−1 spectral window. This facility is now located at Kitt Peak in Arizona and operated remotely from Madison, Wisconsin, 2400 km distant. Early results include a velocity-resolved Hα map of a 70° × 100° region of the sky near the Galactic anticentre, the first detections of Hα emission from the M I and A high velocity clouds, and the first detections of [O I] λ6300 and other faint ‘diagnostic’ lines from the warm ionised medium. Through the summer of 1998, WHAM will be devoted almost exclusively to a survey of the northern sky, which will provide maps of the distribution and kinematics of the diffuse HII through the optical Hα line in a manner that is analogous to earlier sky surveys of the HI made through the 21 cm line.

Revisiting the innermost kinematics of M31 galaxy with the OMM Fabry-Perot interferometer

2019 ◽  
Vol 14 (S353) ◽  
pp. 130-133
Author(s):  
Sié Zacharie Kam ◽  
Claude Carignan ◽  
Michel Marcelin ◽  
Philippe Amram ◽  
Jean Koulidiati
Keyword(s):  
Rotation Curve ◽  
Narrow Band ◽  
Optical Emission ◽  
Emission Lines ◽  
Interference Filters ◽  
Andromeda Galaxy ◽  
Fabry Perot ◽  
The Galaxy ◽  
Data Points ◽  
Made In

AbstractWe present observations on optical emission lines acquired with the scanning Fabry-Perot interferometer of the observatoire du Mont Mégantic, of the Andromeda galaxy (M31). A 765 order Fabry-Perot were used with a fast readout EM-CCD. From data obtained, kinematic maps and data points for the rotation curve of the innermost part of the galaxy are derived. Several dozen of regions have been scanned with the Fabry-Perot interferometer and narrow band interference filters. The central 10’x10’ were scanned with five different filters. Observations have been made in order to get better Hα data for kinematics purposes.

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
Keyword(s):  
Supernova Remnants ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Optical Observations ◽  
Type I ◽  
Radiative Shock ◽  
Neutral Gas ◽  
The Galaxy ◽  
Hα Emission ◽  
Very High

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.

scholarly journals Searching for Supernova Remnants

1998 ◽  
Vol 15 (1) ◽  
pp. 79-82 ◽  
Author(s):  
A. Walker ◽  
W. J. Zealey
Keyword(s):  
Supernova Remnants ◽  
Supernova Remnant ◽  
Galactic Plane ◽  
Chemical Properties ◽  
Optical Emission ◽  
Composite Image ◽  
Large Numbers ◽  
The Galaxy ◽  
Physical And Chemical ◽  
And Chemical Properties

AbstractThe UKST/AAO Galactic Plane Hα Survey has the potential to discover many new objects not visible on red plates taken in past surveys. Recent radio surveys have identified large numbers of new supernova remnants, very few of which have been optically identified. Here we will discuss our plans to use this survey to search for optical emission from both new and known supernova remnants. Observations of these objects in the optical and radio wavelengths will reveal important information about the physical and chemical properties of supernova remnants, and their role in the evolution of the galaxy. We also present a composite image of a newly discovered Hα shell around the Coalsack, named the Coalsack Loop. This object has been detected in radio emission and may represent the remains of an old supernova remnant.

scholarly journals Multi-wavelength View of the Interstellar Medium in the Large Magellanic Cloud

1998 ◽  
Vol 15 (1) ◽  
pp. 136-140
Author(s):  
You-Hua Chu
Keyword(s):  
Interstellar Medium ◽  
Supernova Remnants ◽  
Optical Emission ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Radio Continuum ◽  
Emission Lines ◽  
X Rays ◽  
Multi Wavelength ◽  
The Relationship

AbstractThe Large Magellanic Cloud (LMC) has been surveyed in optical emission lines, X-rays, radio continuum, HI, and CO lines. These surveys provide views of the interstellar medium (ISM) in the LMC of unprecedented clarity, allowing us to study astrophysical processes and to examine the relationship among the different phases of the ISM. Multi-wavelength images are used to illustrate the physical structures of supernova remnants, superbubbles, and supergiant shells, as well as the global interstellar structure of the LMC.

scholarly journals Super-Keplerian equatorial outflows in SS 433

2019 ◽  
Vol 623 ◽  
pp. A47 ◽  
Author(s):  
Idel Waisberg ◽  
Jason Dexter ◽  
Pierre-Olivier Petrucci ◽  
Guillaume Dubus ◽  
Karine Perraut
Keyword(s):  
Angular Momentum ◽  
Near Infrared ◽  
Line Emission ◽  
Optical Emission ◽  
Emission Lines ◽  
High Spectral Resolution ◽  
Wind Component ◽  
Ss 433 ◽  
Rotation Direction ◽  
Very High

Context. The microquasar SS 433 is the only known steady supercritical accretor in the Galaxy. It is well-known for its relativistic baryonic jets, but the system also drives equatorial outflows. These have been routinely detected in radio images, and components associated with a circumbinary disk have also been suggested in optical emission lines. Aims. We aim to spatially resolve the regions producing the stationary emission lines of SS 433 to shed light on its circumbinary structure and outflows. With an estimated binary orbit size of ≲0.1 mas, this requires optical interferometry. Methods. We use the optical interferometer VLTI+GRAVITY to spatially resolve SS 433 in the near-infrared K band at high spectral resolution (R ≈ 4000) on three nights in July 2017. This is the second such observation, after the first one in July 2016. Results. The stationary Brγ line in the 2017 observation is clearly dominated by an extended ∼1 mas ∼ 5 AU circumbinary structure perpendicular to the jets with a strong rotation component. The rotation direction is retrograde relative to the jet precession, in accordance with the slaved disk precession model. The structure has a very high specific angular momentum and is too extended to be a stable circumbinary disk in Keplerian rotation; interpreting it as such leads to a very high enclosed mass M ≳ 400 M⊙. We instead interpret it as the centrifugal ejection of the circumbinary disk, with the implication that there must be an efficient transfer of specific angular momentum from the binary to the disk. We suggest that the equatorial outflows sometimes seen in radio images result from similar episodes of circumbinary disk centrifugal ejection. In addition to the equatorial structure, we find a very extended ∼6 mas ∼ 30 AU spherical wind component to the Brγ line: the entire binary is engulfed in an optically thin spherical line emission envelope.

scholarly journals Supernova Remnants in the Magellanic Clouds Observed at the Molonglo Observatory

1987 ◽  
Vol 125 ◽  
pp. 130-130 ◽  
Author(s):  
A.J. Turtle
Keyword(s):  
Radio Emission ◽  
Supernova Remnants ◽  
Large Diameter ◽  
Optical Emission ◽  
Magellanic Clouds ◽  
Emission Lines ◽  
Type I ◽  
Hii Region ◽  
X Ray ◽  
Central Concentration

Radio surveys of the Magellanic Clouds at 843 MHz have been made with the Molonglo Observatory Synthesis Telescope. An initial catalogue (Mills et al. 1984) presented details of 38 supernova remnants detected by a combination of X-ray, optical and radio observations. The subsequent completion of the radio survey has revealed at least a further 17 remnants, mainly of large diameter and undetected by the Einstein X-ray Observatory. Though a few remnants have their radio emission concentrated towards their centre there is no evidence in the Magellanic Clouds for a Crab-like plerion (without an associated shell). The two well-established plerions 0540-693 (with optical and X-ray pulsar) and 0538-691 (N157B) appear to be connected with partial shells of strong radio emission which are relatively weak in optical emission lines (0538-691 is superposed on an HII region). Four sources which have a central concentration show larger optical and X-ray shells. The optical spectra of three of these (0505-679, 0509-675 and 0519-690) are dominated by the emission lines of hydrogen and Tuohy et al. (1982) argue that they are remnants of Type I supernovae. The fourth source (0453-685) which has detectable [OIII] emission may be an older but similar type of remnant. A further remnant 0509-687 (N103B) is compact but its radio diameter of 6 pc agrees with the published X-ray result.

scholarly journals PS1-13cbe: the rapid transition of a Seyfert 2 to a Seyfert 1

2019 ◽  
Vol 487 (3) ◽  
pp. 4057-4070
Author(s):  
Reza Katebi ◽  
Ryan Chornock ◽  
Edo Berger ◽  
David O Jones ◽  
Ragnhild Lunnan ◽  
...  
Keyword(s):  
Optical Emission ◽  
Sloan Digital Sky Survey ◽  
Emission Lines ◽  
Late Time ◽  
Tidal Disruption ◽  
Transient Event ◽  
Sky Survey ◽  
The Galaxy ◽  
Optical Continuum ◽  
Rapid Transition

ABSTRACT We present a nuclear transient event, PS1-13cbe, that was first discovered in the Pan-STARRS1 survey in 2013. The outburst occurred in the nucleus of the galaxy SDSS J222153.87+003054.2 at z = 0.123 55, which was classified as a Seyfert 2 in a pre-outburst archival Sloan Digital Sky Survey (SDSS) spectrum. PS1-13cbe showed the appearance of strong broad H α and H β emission lines and a non-stellar continuum in a Magellan spectrum taken 57 d after the peak of the outburst that resembled the characteristics of a Seyfert 1. These broad lines were not present in the SDSS spectrum taken a decade earlier and faded away within 2 yr, as observed in several late-time MDM spectra. We argue that the dramatic appearance and disappearance of the broad lines and a factor of ∼8 increase in the optical continuum are most likely caused by variability in the pre-existing accretion disc than a tidal disruption event, supernova, or variable obscuration. The time-scale for the turn-on of the optical emission of ∼70 d observed in this transient is among the shortest observed in a ‘changing-look’ active galactic nucleus.

scholarly journals Observations of Supernova Remnants With ISO

1998 ◽  
Vol 11 (2) ◽  
pp. 1148-1150
Author(s):  
R.J. Tuffs
Keyword(s):  
Supernova Remnants ◽  
Blast Waves ◽  
Optical Observations ◽  
Core Collapse ◽  
Cygnus Loop ◽  
Radiative Shocks ◽  
Main Emphasis ◽  
The Galaxy ◽  
First Results ◽  
Cas A

Pointed observations with ISO have been made, or are planned, towards 58 supernova remnants (SNRs) in the galaxy and Magellanic clouds. The main emphasis is on detailed studies of gas, dust and synchrotron emission from selected regions within 24 well studied galactic remants. First results are available for Cas A (Lagage et al. 1996, 1997; Tuffs et al. 1997; Unger et al. 1997), the Cygnus Loop (deCourchelle et al 1997; Fischera et al. 1997), RCW103 (Oliva et al. 1997; Wright et al. 1997), and W44 and 3C391 (Reach and Rho 1996). These are providing insights into issues such as the yield and composition of condensates in supernova ejecta, the processing of grains by adiabatic and radiative shocks, and the measurement of cold gas, inaccessible to optical observations, both from cool regions in radiative shocks and from unshocked ejecta. In this progress report these points are illustrated with reference to Cas A, the prototype of an ejecta-dominated remnant of a massive core-collapse supernova, and the Cygnus Loop and RCW103 as prime examples of radiative shocks delineating the interaction of fast blast waves with diffuse atomic and dense molecular clouds, respectively.

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