The Sizes of OH (1720 MHz) Supernova Remnant Masers: MERLIN and Very Long Baseline Array Observations of IC 443

Hoffman, Ian M.; Goss, W. M.; Brogan, C. L.; Claussen, M. J.; Richards, A. M. S.

doi:10.1086/345355

Cited by 26 publications

(17 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…11 we conclude that there is not a simple association between maser locations and spectral index features but rather both flat and steep components are observed near masers areas. This fact can be compared with previous results, which suggest that maser regions in IC 443 arise from regions with different shock geometry: a shock mostly propagating towards the line of sight in the southern OH maser emission and a transverse shock in the westernmost OH emitting region (Claussen et al 1997;Hoffman et al 2003;Hewitt 2009) flat spectrum emission (α 330 74 = −0.4) is observed towards the easternmost OH maser area with tangential shock (RA = 06 h 18 m 3. s 67, Dec = +22 • 25 53. 4) can be explained because in this region thermal electrons mask the intrinsic SNR spectral effects.…”

Section: Comparison With the Molecular Distributionsupporting

confidence: 68%

High-resolution radio study of SNR IC 443 at low radio frequencies

Castelletti

Dubner

Kassim

2011

A&A

View full text Add to dashboard Cite

Aims. We investigate the morphology at low radio frequencies of the supernova remnant (SNR) IC 443 in detail and accurately establish its radio continuum spectral properties. Methods. We used the VLA in multiple configurations to produce high-resolution radio images of IC 443 at 74 and 330 MHz. From these data we produced the first sensitive, spatially resolved spectral analysis of the radio emission at long wavelengths. The changes with position in the radio spectral index were correlated with data in near infrared (NIR) from 2MASS, in gamma-rays from VERITAS, and with the molecular 12 CO (J = 1−0) line emission. With the available statistics the VERITAS γ-ray emission strikingly matches the CO distribution, but no clear evidence is found for a morphological correlation between the TeV distribution and radio emission. Conclusions. The excellent correspondence between the eastern radio flattest spectrum region and NIR ionic lines strongly suggests that the passage of a fast, dissociating J-type shock across the interacting molecular cloud dissociated the molecules and ionized the gas. We therefore conclude that thermal absorption at 74 MHz (τ 74 up to ∼0.3) is responsible for the localized spectral index flattening observed along the eastern border of IC 443. Towards the interior of IC 443, the spectrum is consistent with those expected from linear diffusive shock acceleration, while the flatter spectrum in the southern ridge is a consequence of the strong shock/molecular cloud interaction.

show abstract

Section: Comparison With the Molecular Distributionsupporting

confidence: 68%

High-resolution radio study of SNR IC 443 at low radio frequencies

Castelletti

Dubner

Kassim

2011

A&A

View full text Add to dashboard Cite

show abstract

“…A rich spectrum of molecular lines emission (van Dishoeck et al 1993;Rho et al 2001 and references therein), together with OH (1720 MHz) maser emission (Claussen et al 1997;Hoffman et al 2003), has been detected, confirming the interaction with high-density gas. In the northeast the shock front has encountered a less dense (10 < n 0 < 10 3 cm…”

Section: à3mentioning

confidence: 58%

XMM‐NewtonObservations of the Supernova Remnant IC 443. I. Soft X‐Ray Emission from Shocked Interstellar Medium

Troja

Bocchino

Reale

2006

ApJ

129

View full text Add to dashboard Cite

The shocked interstellar medium around IC 443 produces strong X-ray emission in the soft energy band (E P 1:5 keV). We present an analysis of such emission as observed with the EPIC MOS cameras on board the XMMNewton observatory, with the purpose to find clear signatures of the interactions with the interstellar medium (ISM) in the X-ray band, which may complement results obtained in other wavelengths. We found that the giant molecular cloud mapped in CO emission is located in the foreground and gives an evident signature in the absorption of X-rays. This cloud may have a torus shape, and the part of torus interacting with the IC 443 shock gives rise to 2MASS K s emission in the southeast. The measured density of emitting X-rayYshocked plasma increases toward the northeastern limb, where the remnant is interacting with an atomic cloud. We found an excellent correlation between emission in the 0.3Y0.5 keV band and bright optical/radio filament on large spatial scales. The partial shell structure seen in this band therefore traces the encounter with the atomic cloud. Subject headingg s: ISM: individual (IC 443) -supernova remnants -X-rays: ISM

show abstract

“…The location of this OH maser line, which Hoffman et al (2003) revisited, corresponds to offsets (20 , 60 ) from our reference coordinates for IC 443-G. At that location we obtained a polarization angle of 29…”

Section: Discussionmentioning

confidence: 90%

Non-Zeeman circular polarization of CO rotational lines in SNR IC 443

Hezareh

Wiesemeyer

Houde

et al. 2013

A&A

View full text Add to dashboard Cite

Context. We study interstellar magnetic fields by measuring the polarization in molecular spectral lines and thermal emission of dust. Aims. We report detection of non-Zeeman circular polarization and linear polarization levels of up to 1% in the 12 CO spectral line emission in a shocked molecular clump around the supernova remnant (SNR) IC 443. We examine our polarization results to confirm that the circular polarization signal in CO lines is caused by a conversion of linear to circular polarization, consistent with anisotropic resonant scattering. In this process background, linearly polarized CO emission interacts with similar foreground molecules aligned with the ambient magnetic field and scatters at a transition frequency. The difference in phase shift between the orthogonally polarized components of this scattered emission can cause a transformation of linear to circular polarization. Methods. We compared linear polarization maps from the dust continuum, which were obtained with PolKa at APEX, and 12 CO (J = 2 → 1) and (J = 1 → 0) from the IRAM 30-m telescope. We found no consistency between the two sets of polarization maps. We then reinserted the measured circular polarization signal in the CO lines across the source to the corresponding linear polarization signal to test whether the linear polarization vectors of the CO maps were aligned with those of the dust before this linear to circular polarization conversion. Results. After the flux correction for the two transitions of the CO spectral lines, the new polarization vectors for both CO transitions aligned with the dust polarization vectors, establishing that the non-Zeeman CO circular polarization is due to a linear to circular polarization conversion.

show abstract

The Sizes of OH (1720 MHz) Supernova Remnant Masers: MERLIN and Very Long Baseline Array Observations of IC 443

Cited by 26 publications

References 56 publications

High-resolution radio study of SNR IC 443 at low radio frequencies

High-resolution radio study of SNR IC 443 at low radio frequencies

XMM‐NewtonObservations of the Supernova Remnant IC 443. I. Soft X‐Ray Emission from Shocked Interstellar Medium

Non-Zeeman circular polarization of CO rotational lines in SNR IC 443

Contact Info

Product

Resources

About