Continuation of a survey of OH (1720 MHz) Maser Emission Towards = Remnants

Green, Anne; Frail, D. A.; Goss, W. M.; Otrupcek, Robina E.

doi:10.1086/118626

Cited by 190 publications

(263 citation statements)

References 0 publications

Supporting

Mentioning

246

Contrasting

Order By: Relevance

“…Evidence that mixed-morphology SNRs produce OH masers has been recently accumulating (e.g., Yusef-Zadeh et al 2003 (Green et al 1997). Similarly, we find that the 12 CO 2-1/1-0 ratio (after converting the antenna temperature into brightness temperature) is quite homogeneous throughout the field and is about 0.87.…”

Section: Origg In Of the Soft And Hard Componentssupporting

confidence: 75%

ChandraSpatially Resolved Spectroscopic Study and Multiwavelength Imaging of the Supernova Remnant 3C 397 (G41.1−0.3)

Safi‐Harb

Dubner

Petre

et al. 2005

ApJ

View full text Add to dashboard Cite

We present a Chandra observation of the supernova remnant (SNR) 3C 397 (G41.1À0.3) obtained with the Advanced CCD Imaging Spectrometer (ACIS-S). Previous studies of this SNR have shown that the remnant harbors a central X-ray ''hot spot'' suggestive of a compact object associated with 3C 397. With the Chandra data, we can rule out the nature of the hot spot as a pulsar or a pulsar wind nebula and put an upper limit on the flux of a hidden compact object of F X (0:5 10 keV ) $ 6 ; 10 À13 ergs cm À2 s À1 . We found two point sources in the observed Chandra field. We argue that neither of them is associated with 3C 397 and that the hard source, CXO J190741.2+070650, which is characterized by a heavily absorbed spectrum with a strong Fe line, is a newly discovered active galactic nucleus. The Chandra image reveals arcsecond-scale clumps and knots that are strongly correlated with the radio VLA image, except for the X-ray hot spot. Our Chandra spatially resolved spectroscopic study shows that one-component models are inadequate and that at least two nonequilibrium ionization thermal components are needed to fit the spectra of each selected region. The derived average spectral parameters are consistent with the previous global ASCA fits performed by Safi-Harb and coworkers. However, the hard component requires a high abundance of Fe indicating the presence of hot Fe ejecta. When comparing the eastern with the western lobe, we find that the column density, the brightness, and the ionization timescales are generally higher for the western side. This result, combined with our study of the 3C 397 environs at millimeter wavelengths, indicates a denser medium to the west of the SNR. Our multiwavelength imaging and spectral study favors the scenario in which 3C 397 is a $5300 year old SNR expanding in a medium with a marked density gradient and is likely to be encountering a molecular cloud on the western side. We propose that 3C 397 will evolve into a mixed-morphology SNR. Subject headingg s: ISM: individual (G41.1À0.3, 3C 397) -stars: neutron -supernova remnants -X-rays: ISM

show abstract

Section: Origg In Of the Soft And Hard Componentssupporting

confidence: 75%

ChandraSpatially Resolved Spectroscopic Study and Multiwavelength Imaging of the Supernova Remnant 3C 397 (G41.1−0.3)

Safi‐Harb

Dubner

Petre

et al. 2005

ApJ

View full text Add to dashboard Cite

show abstract

“…Among 190 SNRs that have been searched for OH (1720 MHz) maser emission; 19 detections are found in the disk and in the Galactic center (e.g., Green et al 1997;Yusef-Zadeh et al 1996. Table 1 shows the names of all 19 known ME SNRs and their corresponding X-ray characteristics compiled from observations using ASCA, ROSAT, and Einstein data.…”

Section: An Association Between MM and Me Snrsmentioning

confidence: 99%

“…The necessary OH abundance in the shocked gas (OH=H 2 e10 À6 ) is created by the dissociation of shockproduced water induced by thermal X-rays emitted from the hot gas filling the adjacent supernova remnant (Wardle 1999). Nineteen remnants (about 1 in 10) have 1720 MHz masers and are therefore likely to be interacting with clouds Green et al 1997;Koralesky et al 1998;Yusef-Zadeh et al 1999). The inferred interactions have been confirmed by follow-up searches for millimeter or infrared emission from hot molecular gas or from molecules produced by the rich chemistry occurring within the shock front (e.g., Reach & Rho 1998;Frail & Mitchell 1998;Reynoso & Mangum 2000;Yusef-Zadeh et al 2001;Lazendic et al 2002).…”

Section: Introductionmentioning

confidence: 99%

OH (1720 MHz) Masers and Mixed‐Morphology Supernova Remnants

Yusef‐Zadeh

Wardle

Rho

et al. 2003

ApJ

107

View full text Add to dashboard Cite

Radio surveys of supernova remnants (SNRs) in the Galaxy have uncovered 19 SNRs accompanied by OH maser emission at 1720 MHz. This unusual class of maser sources is suggested to be produced behind a shock front from the expansion of a supernova remnant running into a molecular cloud. An important ingredient of this model is that X-ray emission from the remnant enhances the production of OH molecules. The role of X-ray emission from maser-emitting (ME) SNRs is investigated by comparing the X-ray-induced ionization rate with the theory. One aspect of this model is verified: there is a strong association between ME and mixed-morphology or thermal composite SNRs-center-filled thermal X-ray emission surrounded by shell-like radio morphology. We also present ROSAT and ASCA observations of two ME SNRs: G21.8À0.6 (Kes 69) and G357.7À0.1 (Tornado).

show abstract

“…Also, some evolved stars show maser emission at 1665 and 1667 MHz (e.g., Hu 1994; Deacon et al 2004), the velocities of which are close to that of the 1612 MHz masers (Deacon et al 2004). The 1720 MHz OH masers are best known to be associated with shocks created by SNRs interacting with surrounding molecular clouds (Frail et al 1996;Green et al 1997). The 1720 MHz maser transition has never been detected in AGB stars and is extremely rare in other evolved sources, i.e., it has only been detected in one post-AGB star (OH009.1−0.4; IRAS 18043−2116; Sevenster & Chapman 2001) and one Planetary Nebula (PN) (K 3−35; Gómez et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Unusual Shock-Excited Oh Maser Emission in a Young Planetary Nebula

Qiao

Walsh

Gómez

et al. 2016

ApJ

View full text Add to dashboard Cite

We report on OH maser emission toward G336.644−0.695 (IRAS 16333−4807), which is a H 2 O maser-emitting Planetary Nebula (PN). We have detected 1612, 1667, and 1720 MHz OH masers at two epochs using the Australia Telescope Compact Array, hereby confirming it as the seventh known case of an OH-maser-emitting PN. This is only the second known PN showing 1720 MHz OH masers after K 3−35 and the only evolved stellar object with 1720 MHz OH masers as the strongest transition. This PN is one of a group of very young PNe. The 1612 MHz and 1667 MHz masers are at a similar velocity to the 22 GHz H 2 O masers, whereas the 1720 MHz masers show a variable spectrum, with several components spread over a higher velocity range (up to 36 km s −1 ). We also detect Zeeman splitting in the 1720 MHz transition at two epochs (with field strengths of ∼2 to ∼10 mG), which suggests the OH emission at 1720 MHz is formed in a magnetized environment. These 1720 MHz OH masers may trace short-lived equatorial ejections during the formation of the PN.

show abstract

Continuation of a survey of OH (1720 MHz) Maser Emission Towards = Remnants

Cited by 190 publications

References 0 publications

ChandraSpatially Resolved Spectroscopic Study and Multiwavelength Imaging of the Supernova Remnant 3C 397 (G41.1−0.3)

ChandraSpatially Resolved Spectroscopic Study and Multiwavelength Imaging of the Supernova Remnant 3C 397 (G41.1−0.3)

OH (1720 MHz) Masers and Mixed‐Morphology Supernova Remnants

Unusual Shock-Excited Oh Maser Emission in a Young Planetary Nebula

Contact Info

Product

Resources

About