THE RADIO-2 mm SPECTRAL INDEX OF THE CRAB NEBULA MEASURED WITH GISMO

Journal Article · Fri Jun 10 04:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/734/1/54· OSTI ID:21576683

Arendt, R G ^[1]; George, J V ^[2]; Staguhn, J G; Benford, D J; Fixsen, D J; Maher, S F; Moseley, S H; Sharp, E; Wollack, E J ^[3]; Devlin, M J; Dicker, S R; Korngut, P M ^[4]; Irwin, K D ^[5]; Jhabvala, C A; Miller, T M ^[6]; Kovacs, A ^[7]; Mason, B S ^[8]; Navarro, S; Sievers, A ^[9]

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1. CRESST, University of Maryland-Baltimore County, Baltimore, MD 21250 (United States)
2. Department of Astronomy, University of Maryland-College Park, College Park, MD 20742 (United States)
3. NASA Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States)
4. Department of Physics and Astronomy, University of Pennsylvania, Physics and Astronomy, 209 South 33rd Street, Philadelphia, PA 19104 (United States)
5. NIST Quantum Devices Group, 325 Broadway Mailcode 817.03, Boulder, CO 80305 (United States)
6. NASA Goddard Space Flight Center, Code 553, Greenbelt, MD 20771 (United States)
7. Department of Astronomy, University of Minnesota, 116 Church St SE, Minneapolis, MN 55414 (United States)
8. National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States)
9. Instituto Radioastronomia Milimetrica (IRAM), Av. Divina Pastora 7, Nucleo Central, 18012 Granada (Spain)

We present results of 2 mm observations of the Crab Nebula, obtained using the Goddard-IRAM Superconducting 2 Millimeter Observer (GISMO) bolometer camera on the IRAM 30 m telescope. Additional 3.3 mm observations with the MUSTANG bolometer array on the Green Bank Telescope are also presented. The integrated 2 mm flux density of the Crab Nebula provides no evidence for the emergence of a second synchrotron component that has been proposed. It is consistent with the radio power-law spectrum, extrapolated up to a break frequency of log ({nu}{sub b}[GHz]) = 2.84 {+-} 0.29 or {nu}{sub b} = 695{sup +651}{sub -336} GHz. The Crab Nebula is well resolved by the {approx}16.''7 beam (FWHM) of GISMO. Comparison to radio data at comparable spatial resolution enables us to confirm significant spatial variation of the spectral index between 21 cm and 2 mm. The main effect is a spectral flattening in the inner region of the Crab Nebula, correlated with the toroidal structure at the center of the nebula that is prominent in the near-IR through X-ray regime.

• OSTI ID: 21576683
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 734; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
79 ASTRONOMY AND ASTROPHYSICS
COSMIC RADIO SOURCES
CRAB NEBULA
FLUX DENSITY
NEBULAE
RESOLUTION
SPATIAL RESOLUTION
SUPERNOVA REMNANTS