机构:
NASA, Ames Res Ctr, Astrophys Branch, MS 245-6, Moffett Field, CA 94035 USANASA, Ames Res Ctr, Astrophys Branch, MS 245-6, Moffett Field, CA 94035 USA
Bregman, Jesse D.
[1
]
Bregman, Joel N.
论文数: 0引用数: 0
h-index: 0
机构:
Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USANASA, Ames Res Ctr, Astrophys Branch, MS 245-6, Moffett Field, CA 94035 USA
Bregman, Joel N.
[2
]
Temi, Pasquale
论文数: 0引用数: 0
h-index: 0
机构:
NASA, Ames Res Ctr, Astrophys Branch, MS 245-6, Moffett Field, CA 94035 USA
SETI Inst, Mountain View, CA 94043 USA
Univ Western Ontario, Dept Phys & Astron, London, ON N6A 3K7, CanadaNASA, Ames Res Ctr, Astrophys Branch, MS 245-6, Moffett Field, CA 94035 USA
Temi, Pasquale
[1
,3
,4
]
机构:
[1] NASA, Ames Res Ctr, Astrophys Branch, MS 245-6, Moffett Field, CA 94035 USA
[2] Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA
[3] SETI Inst, Mountain View, CA 94043 USA
[4] Univ Western Ontario, Dept Phys & Astron, London, ON N6A 3K7, Canada
In a sample of thirty normal elliptical galaxies observed with the Spitzer IRS, one galaxy, NGC4697, shows strong PAH emission, but with an apparently weak 7.7 mu m feature. We find that the PAH emission is confined to the central regions of the galaxy and that once a quiescent elliptical galaxy spectrum is subtracted, the PAH feature ratios are normal. We show that the PAH spectrum resembles the diffuse ISM of our galaxy rather than an HII region, and is not indicative of a starburst galaxy. We suggest that the PAHs in NGC4697 are consistent with a recent but now past burst of star formation.