Related papers: Hard X-ray observations of Extremely Red Objects

Wide field near-infrared (IR) surveys have revealed a population of galaxies with very red optical$-$IR colors, which have been termed ``Extremely Red Objects'' (EROs). Modeling suggests that such red colors (R-K > 5) could be produced by…

We present predictions for the clustering of Extremely Red Objects (EROs) in a \Lambda cold dark matter Universe, using a semi-analytical galaxy formation model in combination with a cosmological N-body simulation. EROs are red, massive…

We are carrying on a near-IR very low resolution spectroscopic follow-up in parallel with XMM-Newton observations of a complete sample of ~30 bright (K'<18.5) Extremely Red Objects (EROs) selected over an area of 360 arcmin^2 of the MUNICS…

The NASA/ISO Key Project on active galactic nuclei (AGN) seeks to better understand the broad-band spectral energy distributions (SEDs) of these sources from radio to X-rays, with particular emphasis on infrared properties. The ISO sample…

We use a serendipitously discovered overdensity of extremely red objects (EROs) to study the morphologies and cumulative surface number density of EROs in a dense environment. Our extremely deep imaging allows us to select very faint EROs,…

Within the framework of our program of assessment of the nature of unidentified or poorly known INTEGRAL sources, we present here spectroscopy of optical objects, selected through positional cross-correlation with soft X-ray detections…

X-rays provide a robust method in identifying AGN. However, in the high-redshift Universe, their space density is relatively low, and, in combination with the small areas covered by X-ray surveys, the selected AGN are poorly sampled. Deep…

We measure the near-infrared properties of 42 X-ray detected sources from the Chandra Deep Fields North and South, the majority of which lie within the NICMOS Hubble Deep Field North and Ultra Deep Field. We detect all 42 Chandra sources…

[abridged] The properties of galaxies with the reddest observed R-K colors (Extremely Red Objects, EROs), including their apparent division into passive and obscured active objects with roughly similar number densities, are a known…

We identify sources with extremely hard X-ray spectra (i.e., with photon indices of Gamma<0.6 in the 13 sq. deg. NuSTAR serendipitous survey, to search for the most highly obscured AGNs detected at >10 keV. Eight extreme NuSTAR sources are…

We present a method based on two broad-band colors to investigate the nature of the Extremely Red Objects (EROs), i.e., the galaxies selected to have very red optical-to-infrared colors. Dusty starburst and old ellipticals at redshifts…

The Two Micron All Sky Survey (2MASS) is finding previously unidentified, luminous red active galactic nuclei (AGN). This new sample has a space density similar to, or greater than, previously known AGN, suggesting that a large fraction of…

We present Chandra and Spitzer data of the 186, extragalactic, hard 2-10 keV X-ray selected sources, which lie in the central part of the Chandra Deep Field South (CDFS). For the vast majority of sources (99.5%) there is a spectroscopic or…

We present the results of Chandra and XMM-Newton observations for six hard X-ray sources (IGR J12134-6015, IGR J18293-1213, IGR J18219-1347, IGR J17350-2045, IGR J18048-1455, XTE J1901+014) from the INTEGRAL all-sky survey. Based on these…

Hard X-ray selection is the most efficient way to discriminate between accretion-powered sources, such as AGN, from sources dominated by starlight. Hard X-rays are also less affected than other bands by obscuration. We have then carried out…

We discuss the submillimeter properties of Extremely Red Objects (EROs) in the two Canada-UK Deep Submillimeter Survey (CUDSS) Fields. We measure the mean submillimeter flux of the ERO population (to K < 20.7) and find 0.4 +/- 0.07 mJy for…

The majority of active galactic nuclei (AGN) are obscured by large amounts of absorbing material that makes them invisible at many wavelengths. X-rays, given their penetrating power, provide the most secure way for finding these AGN. The…

From optical spectroscopy of X-ray sources observed as part of ChaMP, we present redshifts and classifications for a total of 1569 Chandra sources from our targeted spectroscopic follow up using the FLWO, SAAO, WIYN, CTIO, KPNO, Magellan,…

We analyse very deep X-ray and mid-IR surveys in common areas of the Lockman Hole and the HDF North to study the sources of the X-ray background (XRB) and to test the standard obscured accretion paradigm. We detect with ISO a rich…

Hyper-Luminous Infrared Galaxies (HLIRGs) are the most luminous persistent objects in the Universe. They exhibit extremely high star formation rates, and most of them seem to harbour an AGN. They are unique laboratories to investigate…