Bracco, A. and Cooray, A. and Veneziani, M. (2011) Herschel-ATLAS: statistical properties of Galactic cirrus in the GAMA-9 Hour Science Demonstration Phase Field. Monthly Notices of the Royal Astronomical Society, 412 (2). pp. 1151-1161. ISSN 0035-8711. http://resolver.caltech.edu/CaltechAUTHORS:20110426-072521420
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We study the spectral energy distribution (SED) and the power spectrum of Galactic cirrus emission observed in the 14 deg^2 Science Demonstration Phase field of the Herschel-ATLAS using Herschel and IRAS data from 100 to 500 μm. We compare the Spectral and Photometric Imaging Receiver (SPIRE) 250, 350 and 500 μm maps with IRAS 100-μm emission, binned in 6-arcmin pixels. We assume a modified blackbody SED with dust emissivity parameter β (F∝λ^(−β)) and a single dust temperature T_d, and find that the dust temperature and emissivity index varies over the science demonstration field as 10 < T_d < 25K and 1 < β < 4. The latter values are somewhat higher than the range of β often quoted in the literature (1 < β < 2). We estimate the mean values of these parameters to be T_d= 19.0 ± 2.4 K and β= 1.4 ± 0.4. In regions of bright cirrus emission, we find that the dust has similar temperatures with T_d = 18.0 ± 2.5 K, and similar values of β, ranging from 1.4 ± 0.5 to 1.9 ± 0.5. We show that T_d and β associated with diffuse cirrus emission are anti-correlated and can be described by the relationship: β(T_d) =NT^α_d with [N= 116 ± 38, α=−1.4 ± 0.1]. The strong correlation found in this analysis is not just limited to high-density clumps of cirrus emission as seen in previous studies, but is also seen in diffuse cirrus in low-density regions. To provide an independent measure of T_d and β, we obtain the angular power spectrum of the cirrus emission in the IRAS and SPIRE maps, which is consistent with a power spectrum of the form P(k) =P_0(k/k_0)^γ, where γ= 2.6 ± 0.2 for scales of 50–200 arcmin in the SPIRE maps. The cirrus rms fluctuation amplitude at angular scales of 100 arcmin is consistent with a modified blackbody SED with T_d 20.1 ± 0.9 K and β= 1.3 ± 0.2, in agreement with the values obtained above.
|Additional Information:||© 2011 The Authors. Monthly Notices of the Royal Astronomical Society © 2011 RAS. Accepted 2010 November 2. Received 2010 November 2; in original form 2010 September 25. Article first published online: 7 Feb. 2011. The Herschel-ATLAS is a project with Herschel, which is an ESA space observatory with science instruments provided by European led Principal Investigator consortia and with important participation from NASA. The H-ATLAS website is http://www.h-atlas.org/. AA, AB, AC and PS acknowledge support from NASA funds for US participants in Herschel through JPL.|
|Subject Keywords:||methods: statistical; ISM: structure; infrared: ISM|
|Official Citation:||Herschel-ATLAS: statistical properties of Galactic cirrus in the GAMA-9 Hour Science Demonstration Phase Field (pages 1151–1161) A. Bracco, A. Cooray, M. Veneziani, A. Amblard, P. Serra, J. Wardlow, M. A. Thompson, G. White, R. Auld, M. Baes, F. Bertoldi, S. Buttiglione, A. Cava, D. L. Clements, A. Dariush, G. De Zotti, L. Dunne, S. Dye, S. Eales, J. Fritz, H. Gomez, R. Hopwood, I. Ibar, R. J. Ivison, M. Jarvis, G. Lagache, M. G. Lee, L. Leeuw, S. Maddox, M. Michałowski, C. Pearson, M. Pohlen, E. Rigby, G. Rodighiero, D. J. B. Smith, P. Temi, M. Vaccari and P. van der Werf Article first published online: 7 FEB 2011 | DOI: 10.1111/j.1365-2966.2010.17971.x|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Ruth Sustaita|
|Deposited On:||26 Apr 2011 15:04|
|Last Modified:||25 Mar 2014 20:02|
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