Search for sub-mm, mm and radio continuum emission   from extremely red objects

Mohan, Niruj R.; Cimatti, A.; Röttgering, H. J. A.; Andreani, P.; Severgnini, P.; Tilanus, R. P. J.; Carilli, C. L.; Stanford, S. A.

doi:10.1051/0004-6361:20011742

Cited by 25 publications

(30 citation statements)

References 33 publications

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“…This can be compared to the claim that 13% AE 9% of the counterparts to SCUBA galaxies brighter than 2 mJy have K 20:5 and ðRÀKÞ ! 5:3, equivalent to a surface density of $0:11 AE 0:09 arcmin À2 ; see also Mohan et al 2002) and the estimate surface density of EROs brighter than 8 mJy of 0.03 arcmin À2 from Ivison et al (2002). Allowing for the large uncertainties in these estimates and the possible upward revision of the density of radio-selected ULIRGs to account for badly fitted SEDs (including the known SCUBA ERO 01206), we conclude that they are in reasonable agreement.…”

Section: Dusty Eros In the Far-infrared And Submillimetermentioning

confidence: 80%

“…The radio-detected EROs comprise 31% AE 7% of the whole ERO population down to K ¼ 20:5 (see also Yan 2001;Mohan et al 2002), where the error bar is based on Poisson statistics and hence probably underestimates the field-to-field variance in this fraction. Taking the expected blank-field radio counts sources down to 12.6 lJy ($250; Richards 1999), the ERO counterparts with K 20:5 represent $8% of the total radio population.…”

Section: The Radio-detected Erosmentioning

confidence: 99%

“…Techniques to separate the passive, evolved and obscured, active populations include near-infrared photometric classifications Smith et al 2002b;Mannucci et al 2002), submillimeter emission (Dey et al 1999;Mohan et al 2002), X-ray emission (Alexander et al 2001(Alexander et al , 2002Brusa et al 2002), and optical/ near-infrared spectroscopy Smith et al 2001Smith et al , 2002a. Of these approaches, by far the largest and most influential project is the '' K20 '' survey undertaken by Cimatti et al (2002), who obtained spectroscopic classifications for 29 EROs with K < 19:2 and ðRÀKÞ !…”

Section: Introductionmentioning

confidence: 99%

“…Here we apply a new technique to investigate the mix of the ERO population at faint magnitudes: using very deep radio observations at 1.4 GHz, which are both sensitive enough to identify strongly star-forming galaxies out to high redshifts, ze1 2, and yet insensitive to the effects of dust obscuration (Mohan et al 2002;Chapman et al 2002b). Radio surveys to submillijansky flux limits have shown the usefulness of this technique for identifying starforming galaxies in the distant universe: morphological classifications from Hubble Space Telescope (HST) imaging show that many are blue disk galaxies (Windhorst et al 1994;Richards et al 1998;, with optical spectroscopy confirming that these are apparently normal star-forming galaxies at intermediate redshifts (Benn et al 1993;Mobasher et al 1999;Roche, Lowenthal, & Koo 2002b), with a small proportion of AGNs (20% based on their radio morphologies in very high resolution maps from combined VLA and Merlin observations [Muxlow et al 1999], with most of these having blue colors).…”

Section: Introductionmentioning

confidence: 99%

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The Diversity of Extremely Red Objects

Smail

Owen

Morrison

et al. 2002

ApJ

157

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We present the results from a sensitive multiwavelength analysis of the properties of extremely red objects (EROs). Our analysis employs deep RIzJHK photometry of an 8<5 Â 8<5 region to select a sample of 68 EROs with ðRÀKÞ ! 5:3 and brighter than K ¼ 20:5 (5 ). We combine this photometric data set with an extremely deep 1.4 GHz radio map of the field obtained from the VLA. This map reaches a 1 limiting flux density of 3.5 lJy, making it the deepest 1.4 GHz map taken, and is sensitive enough to detect an active galaxy with L 1:4 e10 23 W Hz À1 at z > 1. If powered by a starburst, this radio luminosity is equivalent to a star formation rate of e25 M yr À1 for stars more massive than 5 M . We identify radio counterparts to 21 of the EROs in this field with radio fluxes above 12.6 lJy and resolve one-third of these with our 1>6 FWHM beam. The spectral energy distributions of the majority of these galaxies are consistent with those expected for dust-reddened starbursts at z $ 1. At these redshifts the radio luminosities of these galaxies indicate a median far-infrared luminosity of this population of L FIR e10 12 L , meaning that half of the radio-detected sample are ultraluminous infrared galaxies (ULIRGs). We conclude that e16% AE 5% of the ERO population brighter than K ¼ 20:5 are luminous infrared galaxies (LIRGs) at z $ 1. We also use photometric classification of the colors of the EROs to investigate the mix of dusty active and evolved passive systems in the remaining ERO population that is undetected in our radio map. Based on this we suggest that at least 30% and possibly up to $60% of all EROs with ðRÀKÞ ! 5:3 and K 20:5 are dusty, star-forming systems at ze1. Our best estimate of the star formation density in this highly obscured and optically faint (Re26) population is _ Ã ð0:1 100 M Þ ¼ 0:11 AE 0:03 M yr À1 Mpc À3 , comparable to estimates of that in H-emitting galaxies at z $ 1 and greater than the estimates from UV-selected samples at these epochs. This lends support to the claims of a strong increase in the contribution from obscured systems to the star formation density at high redshifts. Using the observed counts of the radio-detected ERO population, we model the apparent break in the K-band number counts of the whole ERO population at K $ 19 20 and propose that the passive ERO class dominates the total population in a relatively narrow magnitude range around Kd20, with dusty, active EROs making up the bulk of the population at fainter limits.

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Section: Dusty Eros In the Far-infrared And Submillimetermentioning

confidence: 80%

Section: The Radio-detected Erosmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The Diversity of Extremely Red Objects

Smail

Owen

Morrison

et al. 2002

ApJ

157

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“…The ERO population was thought to provide fertile hunting grounds for more submillimeter-bright galaxies at high redshift. Additional observations have not supported this idea, however, with only a relatively small fraction, on the order of 20% (Andreani et al 1999;Mohan et al 2002;D. Thompson 2002, private communication), of the bright EROs (K < 19:5) showing strong submillimeter emission.…”

Section: Introductionmentioning

confidence: 99%

Hubble Space TelescopeWFPC2 Morphologies ofK‐selected Extremely Red Galaxies

Yan

Thompson

2003

ApJ

110

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We selected 115 extremely red objects (EROs) from deep Hubble Space Telescope (HST) WFPC2 archive data combined with ground-based K-band images, with (F814WÀK s ) ! 4, K-band signal-to-noise ratio !5, and a median limiting K s magnitude of $18.7, over a corresponding area of 228 arcmin 2 , for a morphological study of the ERO galaxy population. The survey covered a total of $409 arcmin 2 over 77 separate WFPC2 fields. This is the first complete sample of bright EROs with high-resolution HST morphologies. From a visual morphological classification, we find that 30% AE 5% of our (F814WÀK s ) ! 4 selected sample have morphologies consistent with a pure bulge or bulge-dominated galaxy (equivalent to E/S0), while disks comprise 64% AE 7% of the sample. Only 6% of the EROs remained unclassifiable. Mergers or strongly interacting systems, which includes sources from both classes, make up 17% AE 4% of the full sample. The quantitative Medium Deep Survey profile fitting is consistent with these results. These results highlight the complex nature of optical/near-IR color selected EROs. The dominant component of our sample is composed of disks, not spheroids or strongly interacting systems like HR 10. Using Bruzual & Charlot spectral energy distribution models, we investigated population differences in EROs selected by their (IÀK) versus (RÀK) colors and found that I-band based surveys preferentially select systems with prolonged star formation. Real differences in the surface densities of EROs in R-band and I-band based survey may reflect this color selection effect, complicating the comparisons between and interpretations on the nature of the ERO population. We conclude that only a small fraction of EROs at z $ 1 2 could be passively evolving elliptical galaxies formed at high redshift through a '' monolithic collapse '' mechanism. For the majority of EROs, even if most of their stellar mass is already in place at z $ 1, interaction with the environment and accretion of gas still play important roles in their continuing evolution.

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Clustering and Proto-Clusters in the Early Universe

Röttgering

Breuck

Daddi

et al. 2006

Multiwavelength Mapping of Galaxy Formation and Evolution

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Abstract. The clustering properties of clusters, galaxies and AGN as a function of redshift are briefly discussed. It appears that extremely red objects at z ∼ 1, and objects with J − K > 1.7 and photometric redshifts 2 < z phot < 4 are highly clustered, indicating that a majority of these objects constitutes the progenitors of nearby ellipticals. Similarly clustered seem luminous radio galaxies at z ∼ 1, indicating that these objects comprise a short lived phase in the lifetime of these red objects. The high level of clustering furthermore suggests that distant powerful radio galaxies (e.g. z > 2) might be residing in the progenitors of nearby clusters -proto-clusters. A number of observational projects targetting fields with distant radio galaxies, including studies of Lyα and Hα emitters, Lyman break galaxies and (sub)mm and X-ray emitters, all confirm that such radio galaxies are indeed located in proto-clusters. Estimates of the total mass of the proto-clusters are similar to the masses of local clusters. If the total star formation rate which we estimate for the entire proto-clusters is sustained up to z ∼ 1, the metals in the hot cluster gas of local clusters can easily be accounted for.

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Search for sub-mm, mm and radio continuum emission from extremely red objects

Cited by 25 publications

References 33 publications

The Diversity of Extremely Red Objects

The Diversity of Extremely Red Objects

Hubble Space TelescopeWFPC2 Morphologies ofK‐selected Extremely Red Galaxies

Clustering and Proto-Clusters in the Early Universe

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