Abstract
We present a new method to search for candidate z ≳ 2 Herschel 500 μm sources in the Great Observatories Origins Deep Survey-North field using a S500 μm/S24 μm "color deconfusion" technique. Potential high-z sources are selected against low-redshift ones from their large 500 to 24 μm flux density ratios. By effectively reducing the contribution from low-redshift populations to the observed 500 μm emission, we are able to identify counterparts to high-z 500 μm sources whose 24 μm fluxes are relatively faint. The recovery of known z ≳ 4 starbursts confirms the efficiency of this approach in selecting high-z Herschel sources. The resulting sample consists of 34 dusty star-forming galaxies at z ≳ 2. The inferred infrared luminosities are in the range 1.5 × 1012-1.8 × 1013 L⊙, corresponding to dust-obscured star formation rates (SFRs) of ∼260-3100 M⊙ yr-1 for a Salpeter initial mass function. Comparison with previous SCUBA 850 μm-selected galaxy samples shows that our method is more efficient at selecting high-z dusty galaxies, with a median redshift of z = 3.07 ± 0.83 and with 10 of the sources at z ≳ 4. We find that at a fixed luminosity, the dust temperature is ∼5 K cooler than that expected from the Td relation at z ≲ 1, though different temperature selection effects should be taken into account. The radio-detected subsample (excluding three strong active galactic nucleus) follows the far-infrared (far-IR)/radio correlation at lower redshifts, and no evolution with redshift is observed out to z ∼ 5, suggesting that the far-IR emission is star formation dominated. The contribution of the high-z Herschel 500 μm sources to the cosmic SFR density is comparable to that of (sub)millimeter galaxy populations at z ∼ 2.5 and at least 40% of the extinction-corrected UV samples at z ∼ 4. Further investigation into the nature of these high-z dusty galaxies will be crucial for our understanding of the star formation histories and the buildup of stellar mass at the earliest cosmic epochs.
| Original language | English (US) |
|---|---|
| Article number | 4 |
| Journal | Astrophysical Journal, Supplement Series |
| Volume | 222 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 1 2016 |
| Externally published | Yes |
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Keywords
- galaxies: high-redshift
- galaxies: starburst
- infrared: galaxies
- submillimeter: galaxies
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science
Cite this
IDENTIFICATION of z ≳ 2 Herschel 500 μm SOURCES USING COLOR DECONFUSION. / Shu, X. W.; Elbaz, D.; Bourne, N.; Schreiber, C.; Wang, T.; Dunlop, J. S.; Fontana, A.; Leiton, R.; Pannella, M.; Okumura, K.; Michałowski, M. J.; Santini, P.; Merlin, E.; Buitrago, F.; Bruce, V. A.; Amorin, R.; Castellano, M.; Derriere, S.; Comastri, A.; Cappelluti, Nico; Wang, J. X.; Ferguson, H. C.
In: Astrophysical Journal, Supplement Series, Vol. 222, No. 1, 4, 01.01.2016.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - IDENTIFICATION of z ≳ 2 Herschel 500 μm SOURCES USING COLOR DECONFUSION
AU - Shu, X. W.
AU - Elbaz, D.
AU - Bourne, N.
AU - Schreiber, C.
AU - Wang, T.
AU - Dunlop, J. S.
AU - Fontana, A.
AU - Leiton, R.
AU - Pannella, M.
AU - Okumura, K.
AU - Michałowski, M. J.
AU - Santini, P.
AU - Merlin, E.
AU - Buitrago, F.
AU - Bruce, V. A.
AU - Amorin, R.
AU - Castellano, M.
AU - Derriere, S.
AU - Comastri, A.
AU - Cappelluti, Nico
AU - Wang, J. X.
AU - Ferguson, H. C.
PY - 2016/1/1
Y1 - 2016/1/1
N2 - We present a new method to search for candidate z ≳ 2 Herschel 500 μm sources in the Great Observatories Origins Deep Survey-North field using a S500 μm/S24 μm "color deconfusion" technique. Potential high-z sources are selected against low-redshift ones from their large 500 to 24 μm flux density ratios. By effectively reducing the contribution from low-redshift populations to the observed 500 μm emission, we are able to identify counterparts to high-z 500 μm sources whose 24 μm fluxes are relatively faint. The recovery of known z ≳ 4 starbursts confirms the efficiency of this approach in selecting high-z Herschel sources. The resulting sample consists of 34 dusty star-forming galaxies at z ≳ 2. The inferred infrared luminosities are in the range 1.5 × 1012-1.8 × 1013 L⊙, corresponding to dust-obscured star formation rates (SFRs) of ∼260-3100 M⊙ yr-1 for a Salpeter initial mass function. Comparison with previous SCUBA 850 μm-selected galaxy samples shows that our method is more efficient at selecting high-z dusty galaxies, with a median redshift of z = 3.07 ± 0.83 and with 10 of the sources at z ≳ 4. We find that at a fixed luminosity, the dust temperature is ∼5 K cooler than that expected from the Td relation at z ≲ 1, though different temperature selection effects should be taken into account. The radio-detected subsample (excluding three strong active galactic nucleus) follows the far-infrared (far-IR)/radio correlation at lower redshifts, and no evolution with redshift is observed out to z ∼ 5, suggesting that the far-IR emission is star formation dominated. The contribution of the high-z Herschel 500 μm sources to the cosmic SFR density is comparable to that of (sub)millimeter galaxy populations at z ∼ 2.5 and at least 40% of the extinction-corrected UV samples at z ∼ 4. Further investigation into the nature of these high-z dusty galaxies will be crucial for our understanding of the star formation histories and the buildup of stellar mass at the earliest cosmic epochs.
AB - We present a new method to search for candidate z ≳ 2 Herschel 500 μm sources in the Great Observatories Origins Deep Survey-North field using a S500 μm/S24 μm "color deconfusion" technique. Potential high-z sources are selected against low-redshift ones from their large 500 to 24 μm flux density ratios. By effectively reducing the contribution from low-redshift populations to the observed 500 μm emission, we are able to identify counterparts to high-z 500 μm sources whose 24 μm fluxes are relatively faint. The recovery of known z ≳ 4 starbursts confirms the efficiency of this approach in selecting high-z Herschel sources. The resulting sample consists of 34 dusty star-forming galaxies at z ≳ 2. The inferred infrared luminosities are in the range 1.5 × 1012-1.8 × 1013 L⊙, corresponding to dust-obscured star formation rates (SFRs) of ∼260-3100 M⊙ yr-1 for a Salpeter initial mass function. Comparison with previous SCUBA 850 μm-selected galaxy samples shows that our method is more efficient at selecting high-z dusty galaxies, with a median redshift of z = 3.07 ± 0.83 and with 10 of the sources at z ≳ 4. We find that at a fixed luminosity, the dust temperature is ∼5 K cooler than that expected from the Td relation at z ≲ 1, though different temperature selection effects should be taken into account. The radio-detected subsample (excluding three strong active galactic nucleus) follows the far-infrared (far-IR)/radio correlation at lower redshifts, and no evolution with redshift is observed out to z ∼ 5, suggesting that the far-IR emission is star formation dominated. The contribution of the high-z Herschel 500 μm sources to the cosmic SFR density is comparable to that of (sub)millimeter galaxy populations at z ∼ 2.5 and at least 40% of the extinction-corrected UV samples at z ∼ 4. Further investigation into the nature of these high-z dusty galaxies will be crucial for our understanding of the star formation histories and the buildup of stellar mass at the earliest cosmic epochs.
KW - galaxies: high-redshift
KW - galaxies: starburst
KW - infrared: galaxies
KW - submillimeter: galaxies
UR - http://www.scopus.com/inward/record.url?scp=84955451286&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84955451286&partnerID=8YFLogxK
U2 - 10.3847/0067-0049/222/1/4
DO - 10.3847/0067-0049/222/1/4
M3 - Article
AN - SCOPUS:84955451286
VL - 222
JO - Astrophysical Journal, Supplement Series
JF - Astrophysical Journal, Supplement Series
SN - 0067-0049
IS - 1
M1 - 4
ER -