IRS spectra of two ultraluminous infrared galaxies at z = 1.3

V. Desai, L. Armus, B. T. Soifer, D. W. Weedman, S. Higdon, C. Bian, C. Borys, H. W W Spoon, V. Charmandaris, K. Brand, M. J I Brown, A. Dey, J. Higdon, J. Houck, Buell Tomasson Jannuzi, E. Le Floc'h, M. L N Ashby, H. A. Smith

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

We present low-resolution (64 < R < 124) mid-infrared (8-38 μm) spectra of two z ≈ 1.3 ultraluminous infrared galaxies (ULIRGs) with L 8-1000 μm ≈ 1013 L. The spectra were taken with the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope. Both objects were discovered in the NOAO Deep Wide-Field Survey (NDWFS) Bootes field. MIPS J142824.0+352619 is a bright 160 μm source with a large infrared-to-optical flux density ratio. Previous authors provided evidence for a foreground lens and estimated an amplification of ≲10, although this factor is currently poorly constrained. The 6.2, 7.7, 11.3, and 12.8 μm polycyclic aromatic hydrocarbon (PAH) emission bands in its IRS spectrum indicate a redshift of z ≈ 1.3. The large equivalent width of the 6.2 μm PAH feature indicates that at least 50% of the mid-infrared energy is generated in a starburst, an interpretation supported by a large [Ne II]/[Ne III] ratio and a low upper limit on the X-ray luminosity. SST24 J142827.19+354127.71 has the brightest 24 μm flux (10.55 mJy) among optically faint (R > 20) galaxies in the NDWFS. Its mid-infrared spectrum lacks emission features, but the broad 9.7 μm silicate absorption band places this source at z ≈ 1.3. Optical spectroscopy confirms a redshift of z = 1.293 ± 0.001. Given this redshift, SST24 J142827.19+354127.71 has among the largest rest-frame 5 μm luminosities known. The similarity of its SED to those of known AGN-dominated ULIRGs and its lack of either PAH features or large amounts of cool dust indicate that the mid-infrared emission is dominated by an AGN rather than a starburst.

Original languageEnglish (US)
Pages (from-to)133-139
Number of pages7
JournalAstrophysical Journal
Volume641
Issue number1 I
DOIs
StatePublished - Apr 10 2006
Externally publishedYes

Fingerprint

Indian spacecraft
galaxies
polycyclic aromatic hydrocarbons
silicates
PAH
infrared spectra
silicate
dust
spectroscopy
luminosity
absorption spectra

Keywords

  • Galaxies: active
  • Galaxies: evolution
  • Galaxies: formation
  • Galaxies: starburst infrared: galaxies

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Desai, V., Armus, L., Soifer, B. T., Weedman, D. W., Higdon, S., Bian, C., ... Smith, H. A. (2006). IRS spectra of two ultraluminous infrared galaxies at z = 1.3. Astrophysical Journal, 641(1 I), 133-139. https://doi.org/10.1086/500426

IRS spectra of two ultraluminous infrared galaxies at z = 1.3. / Desai, V.; Armus, L.; Soifer, B. T.; Weedman, D. W.; Higdon, S.; Bian, C.; Borys, C.; Spoon, H. W W; Charmandaris, V.; Brand, K.; Brown, M. J I; Dey, A.; Higdon, J.; Houck, J.; Jannuzi, Buell Tomasson; Le Floc'h, E.; Ashby, M. L N; Smith, H. A.

In: Astrophysical Journal, Vol. 641, No. 1 I, 10.04.2006, p. 133-139.

Research output: Contribution to journalArticle

Desai, V, Armus, L, Soifer, BT, Weedman, DW, Higdon, S, Bian, C, Borys, C, Spoon, HWW, Charmandaris, V, Brand, K, Brown, MJI, Dey, A, Higdon, J, Houck, J, Jannuzi, BT, Le Floc'h, E, Ashby, MLN & Smith, HA 2006, 'IRS spectra of two ultraluminous infrared galaxies at z = 1.3', Astrophysical Journal, vol. 641, no. 1 I, pp. 133-139. https://doi.org/10.1086/500426
Desai V, Armus L, Soifer BT, Weedman DW, Higdon S, Bian C et al. IRS spectra of two ultraluminous infrared galaxies at z = 1.3. Astrophysical Journal. 2006 Apr 10;641(1 I):133-139. https://doi.org/10.1086/500426
Desai, V. ; Armus, L. ; Soifer, B. T. ; Weedman, D. W. ; Higdon, S. ; Bian, C. ; Borys, C. ; Spoon, H. W W ; Charmandaris, V. ; Brand, K. ; Brown, M. J I ; Dey, A. ; Higdon, J. ; Houck, J. ; Jannuzi, Buell Tomasson ; Le Floc'h, E. ; Ashby, M. L N ; Smith, H. A. / IRS spectra of two ultraluminous infrared galaxies at z = 1.3. In: Astrophysical Journal. 2006 ; Vol. 641, No. 1 I. pp. 133-139.
@article{88b459b1dc9a4d80b85704300a9bb177,
title = "IRS spectra of two ultraluminous infrared galaxies at z = 1.3",
abstract = "We present low-resolution (64 < R < 124) mid-infrared (8-38 μm) spectra of two z ≈ 1.3 ultraluminous infrared galaxies (ULIRGs) with L 8-1000 μm ≈ 1013 L⊙. The spectra were taken with the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope. Both objects were discovered in the NOAO Deep Wide-Field Survey (NDWFS) Bootes field. MIPS J142824.0+352619 is a bright 160 μm source with a large infrared-to-optical flux density ratio. Previous authors provided evidence for a foreground lens and estimated an amplification of ≲10, although this factor is currently poorly constrained. The 6.2, 7.7, 11.3, and 12.8 μm polycyclic aromatic hydrocarbon (PAH) emission bands in its IRS spectrum indicate a redshift of z ≈ 1.3. The large equivalent width of the 6.2 μm PAH feature indicates that at least 50{\%} of the mid-infrared energy is generated in a starburst, an interpretation supported by a large [Ne II]/[Ne III] ratio and a low upper limit on the X-ray luminosity. SST24 J142827.19+354127.71 has the brightest 24 μm flux (10.55 mJy) among optically faint (R > 20) galaxies in the NDWFS. Its mid-infrared spectrum lacks emission features, but the broad 9.7 μm silicate absorption band places this source at z ≈ 1.3. Optical spectroscopy confirms a redshift of z = 1.293 ± 0.001. Given this redshift, SST24 J142827.19+354127.71 has among the largest rest-frame 5 μm luminosities known. The similarity of its SED to those of known AGN-dominated ULIRGs and its lack of either PAH features or large amounts of cool dust indicate that the mid-infrared emission is dominated by an AGN rather than a starburst.",
keywords = "Galaxies: active, Galaxies: evolution, Galaxies: formation, Galaxies: starburst infrared: galaxies",
author = "V. Desai and L. Armus and Soifer, {B. T.} and Weedman, {D. W.} and S. Higdon and C. Bian and C. Borys and Spoon, {H. W W} and V. Charmandaris and K. Brand and Brown, {M. J I} and A. Dey and J. Higdon and J. Houck and Jannuzi, {Buell Tomasson} and {Le Floc'h}, E. and Ashby, {M. L N} and Smith, {H. A.}",
year = "2006",
month = "4",
day = "10",
doi = "10.1086/500426",
language = "English (US)",
volume = "641",
pages = "133--139",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1 I",

}

TY - JOUR

T1 - IRS spectra of two ultraluminous infrared galaxies at z = 1.3

AU - Desai, V.

AU - Armus, L.

AU - Soifer, B. T.

AU - Weedman, D. W.

AU - Higdon, S.

AU - Bian, C.

AU - Borys, C.

AU - Spoon, H. W W

AU - Charmandaris, V.

AU - Brand, K.

AU - Brown, M. J I

AU - Dey, A.

AU - Higdon, J.

AU - Houck, J.

AU - Jannuzi, Buell Tomasson

AU - Le Floc'h, E.

AU - Ashby, M. L N

AU - Smith, H. A.

PY - 2006/4/10

Y1 - 2006/4/10

N2 - We present low-resolution (64 < R < 124) mid-infrared (8-38 μm) spectra of two z ≈ 1.3 ultraluminous infrared galaxies (ULIRGs) with L 8-1000 μm ≈ 1013 L⊙. The spectra were taken with the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope. Both objects were discovered in the NOAO Deep Wide-Field Survey (NDWFS) Bootes field. MIPS J142824.0+352619 is a bright 160 μm source with a large infrared-to-optical flux density ratio. Previous authors provided evidence for a foreground lens and estimated an amplification of ≲10, although this factor is currently poorly constrained. The 6.2, 7.7, 11.3, and 12.8 μm polycyclic aromatic hydrocarbon (PAH) emission bands in its IRS spectrum indicate a redshift of z ≈ 1.3. The large equivalent width of the 6.2 μm PAH feature indicates that at least 50% of the mid-infrared energy is generated in a starburst, an interpretation supported by a large [Ne II]/[Ne III] ratio and a low upper limit on the X-ray luminosity. SST24 J142827.19+354127.71 has the brightest 24 μm flux (10.55 mJy) among optically faint (R > 20) galaxies in the NDWFS. Its mid-infrared spectrum lacks emission features, but the broad 9.7 μm silicate absorption band places this source at z ≈ 1.3. Optical spectroscopy confirms a redshift of z = 1.293 ± 0.001. Given this redshift, SST24 J142827.19+354127.71 has among the largest rest-frame 5 μm luminosities known. The similarity of its SED to those of known AGN-dominated ULIRGs and its lack of either PAH features or large amounts of cool dust indicate that the mid-infrared emission is dominated by an AGN rather than a starburst.

AB - We present low-resolution (64 < R < 124) mid-infrared (8-38 μm) spectra of two z ≈ 1.3 ultraluminous infrared galaxies (ULIRGs) with L 8-1000 μm ≈ 1013 L⊙. The spectra were taken with the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope. Both objects were discovered in the NOAO Deep Wide-Field Survey (NDWFS) Bootes field. MIPS J142824.0+352619 is a bright 160 μm source with a large infrared-to-optical flux density ratio. Previous authors provided evidence for a foreground lens and estimated an amplification of ≲10, although this factor is currently poorly constrained. The 6.2, 7.7, 11.3, and 12.8 μm polycyclic aromatic hydrocarbon (PAH) emission bands in its IRS spectrum indicate a redshift of z ≈ 1.3. The large equivalent width of the 6.2 μm PAH feature indicates that at least 50% of the mid-infrared energy is generated in a starburst, an interpretation supported by a large [Ne II]/[Ne III] ratio and a low upper limit on the X-ray luminosity. SST24 J142827.19+354127.71 has the brightest 24 μm flux (10.55 mJy) among optically faint (R > 20) galaxies in the NDWFS. Its mid-infrared spectrum lacks emission features, but the broad 9.7 μm silicate absorption band places this source at z ≈ 1.3. Optical spectroscopy confirms a redshift of z = 1.293 ± 0.001. Given this redshift, SST24 J142827.19+354127.71 has among the largest rest-frame 5 μm luminosities known. The similarity of its SED to those of known AGN-dominated ULIRGs and its lack of either PAH features or large amounts of cool dust indicate that the mid-infrared emission is dominated by an AGN rather than a starburst.

KW - Galaxies: active

KW - Galaxies: evolution

KW - Galaxies: formation

KW - Galaxies: starburst infrared: galaxies

UR - http://www.scopus.com/inward/record.url?scp=33745300017&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33745300017&partnerID=8YFLogxK

U2 - 10.1086/500426

DO - 10.1086/500426

M3 - Article

AN - SCOPUS:33745300017

VL - 641

SP - 133

EP - 139

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1 I

ER -