Discovery of Radio Jets in
                    <i>z</i>
                    ~ 2 Ultraluminous Infrared Galaxies with Deep 9.7 μm Silicate Absorption

Sajina, Anna; Yan, Lin; Lacy, Mark; Huynh, Minh

doi:10.1086/522050

Cited by 40 publications

(74 citation statements)

References 39 publications

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“…The estimated SFRs are consistent with those estimated in other radio-quiet obscured QSOs at high-z (e.g. Ivison et al 1998;Efstathiou 2006;Stevens et al 2005;Polletta et al 2008;Sajina et al 2007b). …”

Section: Sed Modeling and Star Formation Ratesupporting

confidence: 87%

Obscured and powerful AGN and starburst activities at z ~ 3.5

Polletta¹,

Omont²,

Berta³

et al. 2008

A&A

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Aims. Short phases of coeval powerful starburst and AGN activity during the lifetimes of the most massive galaxies are predicted by various models of galaxy formation and evolution. In spite of their recurrence and high luminosity, such events are rarely observed. Finding such systems, understanding their nature, and constraining their number density can provide key constraints to galaxy evolutionary models and insights into the interplay between starburst and AGN activities. Methods. We report the discovery of two sources at z = 3.867 and z = 3.427 that exhibit both powerful starburst and AGN activities. They benefit from multi-wavelength data from radio to X rays from the CFHTLS-D1/SWIRE/XMDS surveys. Follow-up optical and near-infrared spectroscopy, and millimeter IRAM/MAMBO observations are also available. We performed a multi-wavelength analysis of their spectral energy distributions with the aim of understanding the origin of their emission and constraining their luminosities. A comparison with other composite systems at similar redshifts from the literature is also presented. Results. The AGN and starburst bolometric luminosities are ∼1013 L . The AGN emission dominates at X ray, optical, mid-infrared wavelengths, and probably also in the radio. The starburst emission dominates in the far-infrared. The estimated star formation rates range from 500 to 3000 M /yr. The AGN near-infrared and X ray emissions are heavily obscured in both sources with an estimated dust extinction A V ≥ 4, and Compton-thick gas column densities. The two sources are the most obscured and most luminous AGNs detected at millimeter wavelengths currently known. Conclusions. The sources presented in this work are heavily obscured QSOs, but their properties are not fully explained by the standard AGN unification model. In one source, the ultraviolet and optical spectra suggest the presence of outflowing gas and shocks, and both sources show emission from hot dust, most likely in the vicinity of the nucleus. Evidence of moderate, AGN-driven radio activity is also found in both sources. Based on the estimated stellar and black hole masses, the two sources lie on the local M BH −M bulge relation. To remain on this relation as they evolve, their star formation rate has to decrease or stop. Our results support evolutionary models that invoke radio feedback such as the star formation quenching mechanism, and suggest that such a mechanism might play a major role also in powerful AGNs.

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Section: Sed Modeling and Star Formation Ratesupporting

confidence: 87%

Obscured and powerful AGN and starburst activities at z ~ 3.5

Polletta¹,

Omont²,

Berta³

et al. 2008

A&A

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“…This similarity is not surprising given the selection of those samples (very red from R band to 24 mm and mJy) but does S տ 1 24um support our earlier comment that HzRGs are representative of a larger population that experience brief periods of extreme AGN activity and obscured star formation. In fact, some of these 24 mm-selected ULIRGs do host radio-loud AGN (Sajina et al 2007b) but have radio luminosities several orders of magnitudes less than the sources presented here. Additionally, the correlation between the presence of PAH and strong emission from cold dust has been seen in Spitzer-selected type 2 AGN (Lacy et al 2007;Sajina et al 2008).…”

Section: Interpretation and Conclusionmentioning

confidence: 49%

Mid-Infrared Spectra of High-Redshift ( z > 2) Radio Galaxies

Seymour¹,

Ogle²,

Breuck³

et al. 2008

ApJ

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We present the first mid-infrared Spitzer/Infrared Spectrograph (IRS) observations of powerful radio galaxies at . These radio galaxies, 4C ϩ23.56 ( ) and 6C J1908ϩ7220 ( ), both show strong midz 1 2 z p 2.48 z p 3.53 infrared continua, but with 6C J1908ϩ7220 also showing strong PAH emission at rest-frame 6.2 and 7.7 mm. In 4C ϩ23.56 we see no obvious PAH features above the continuum. The PAH emission in 6C J1908ϩ7220 is the among the most distant observed to date and implies that there is a large instantaneous star formation rate (SFR). This is consistent with the strong detection of 6C J1908ϩ7220 at far-IR and sub-mm wavelengths, indicative of large amounts of cold dust, ∼10 9 . Powerful radio galaxies at lower redshifts tend to have weak or M , undetectable PAH features and typically have lower far-IR luminosities. In addition, 4C ϩ23.56 shows moderate silicate absorption as seen in less luminous radio galaxies, indicating . This feature is shifted t p 0.3 ‫ע‬ 0.05 9.7 mm out of the observed wavelength range for 6C J1908ϩ7220. The correlation of strong PAH features with large amounts of cold dust, despite the presence of a powerful AGN, is in agreement with other recent results and implies that star formation at high redshift is, in some cases at least, associated with powerful, obscured AGN.

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“…And although relatively faint AGN may be present without leaving strong signatures in the dust SEDs, only a subset of those should be radio loud. Even optimistic results (e.g., from Sajina et al 2007), imply that only up to about 30% of dusty high-z starburst galaxies may host moderately bright (P 1.4 ≈ 10 25 W Hz −1 , comparable to our sources for magnification factors of order 10) nuclear radio sources that are as bright as or brighter than the star formation itself. In addition, these sources are classified as AGN in the mid-IR.…”

Section: Fir-radio Correlationmentioning

confidence: 56%

Planck’s dusty GEMS: The brightest gravitationally lensed galaxies discovered with thePlanckall-sky survey

Cañameras

Nesvadba

Guery

et al. 2015

A&A

128

193

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We present an analysis of CO spectroscopy and infrared-to-millimetre dust photometry of 11 exceptionally bright far-infrared (FIR) and sub-mm sources discovered through a combination of the Planck all-sky survey and follow-up Herschel-SPIRE imaging -"Planck's Dusty Gravitationally Enhanced subMillimetre Sources". Each source has a secure spectroscopic redshift z = 2.2-3.6 from multiple lines obtained through a blind redshift search with EMIR at the IRAM 30-m telescope. Interferometry was obtained at IRAM and the SMA, and along with optical/near-infrared imaging obtained at the CFHT and the VLT reveal morphologies consistent with strongly gravitationally lensed sources, including several giant arcs. Additional photometry was obtained with JCMT/SCUBA-2 and IRAM/GISMO at 850 µm and 2 mm, respectively. The SEDs of our sources peak near either the 350 µm or 500 µm bands of SPIRE with peak flux densities between 0.35 and 1.14 Jy. All objects are extremely bright isolated point sources in the 18 beam of SPIRE at 250 µm, with apparent FIR luminosities of up to 3 × 10 14 L (not correcting for the lensing effect). Their morphologies, sizes, CO line widths, CO luminosities, dust temperatures, and FIR luminosities provide additional empirical evidence that these are amongst the brightest strongly gravitationally lensed high-redshift galaxies on the sub-mm sky. Our programme extends the successful wide-area searches for strongly gravitationally lensed high-redshift galaxies (carried out with the South Pole Telescope and Herschel) towards even brighter sources, which are so rare that their systematic identification requires a genuine all-sky survey like Planck. Six sources are above the 600 mJy 90% completeness limit of the Planck catalogue of compact sources (PCCS) at 545 and 857 GHz, which implies that these must literally be amongst the brightest high-redshift FIR and sub-mm sources on the extragalactic sky. We discuss their dust masses and temperatures, and use additional WISE 22-µm photometry and template fitting to rule out a significant contribution of AGN heating to the total infrared luminosity. Six sources are detected in FIRST at 1.4 GHz, and the others have sensitive upper limits. Four have flux densities brighter than expected from the local FIR-radio correlation, but in the range previously found for high-z sub-mm galaxies, one has a deficit of FIR emission, and 6 are consistent with the local correlation, although this includes 3 galaxies with upper limits. We attribute this to the turbulent interstellar medium of these galaxies, rather than the presence of radio AGN. The global dust-to-gas ratios and star-formation efficiencies of our sources are predominantly in the range expected from massive, metal-rich, intense, high-redshift starbursts. An extensive multi-wavelength follow-up programme is being carried out to further characterize these sources and the intense star formation within them.Key words. galaxies: high-redshift -galaxies: star formation -galaxies: starburst -submillimeter: galaxies -gravi...

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Discovery of Radio Jets in z ~ 2 Ultraluminous Infrared Galaxies with Deep 9.7 μm Silicate Absorption

Cited by 40 publications

References 39 publications

Obscured and powerful AGN and starburst activities at z ~ 3.5

Obscured and powerful AGN and starburst activities at z ~ 3.5

Mid-Infrared Spectra of High-Redshift ( z > 2) Radio Galaxies

Planck’s dusty GEMS: The brightest gravitationally lensed galaxies discovered with thePlanckall-sky survey

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