We have observed the Extended Chandra Deep Field South (E-CDF-S) using a mosaic of six deep Very Large Array (VLA) pointings at 1.4GHz. In this paper, we present the survey strategy, description of the observations, and the first data release. The observations were performed during June through September of 2007 and included from 15 to 17 ``classic'' VLA antennas and 6 to 11 that had been retrofitted for the Expanded VLA (EVLA). The first data release consists of a 34.1' x 34.1' image and the attendant source catalog. The image achieves an rms sensitivity of 6.4 uJy per 2.8" x 1.6" beam in its deepest regions, with a typical sensitivity of 8 uJy. The catalog is conservative in that it only lists sources with peak flux densities greater than seven times the local rms noise, yet it still contains 464 sources. Nineteen of these are complex sources consisting of multiple components. Cross matching of the catalog to prior surveys of the E-CDF-S confirms the linearity of the flux density calibration, albeit with a slight possible offset (a few percent) in scale. Improvements to the data reduction and source catalog are ongoing, and we intend to produce a second data release in January 2009.
We present a status report on our search for multiple-image QSOs among southern radio sources. Our goal is to identify new lenses for use in studies of cosmology and galaxy structure. To date we have examined 3300 radio sources, identified one probable lens and one probable binary QSO along with about 50 candidates deserving further follow-up.
We report on deep multi-color imaging (R_5-sigma = 26) of the Chandra Deep Field South, obtained with the Wide Field Imager (WFI) at the MPG/ESO 2.2 m telescope on La Silla as part of the COMBO-17 survey. As a result we present a catalog of 63501 objects in a field measuring 31.5' x 30' with astrometry and BVR photometry. A sample of 37 variable objects is selected from two-epoch photometry. We try to give interpretations based on color and variation amplitude.
Because several observing programs are underway in various spectral regimes to explore the Chandra Deep Field South (CDF-S), the value of local photometric standards is obvious. As part of an NOAO Surveys Program to establish u'g'r'i'z' standard stars in the southern hemisphere, we have observed the central region of the CDF-S to create local standards for use by other investigators using these filters. As a courtesy, we present the CDF-S standards to the public now, although the main program will not finish until mid-2005.
Chandra deep fields represent the deepest look at the X-ray sky. We analyzed the Chandra Deep Field South (CDFS) with the aid of a dedicated wavelet-based algorithm. Here we present a detailed description of the procedures used to analyze this field, tested and verified by means of extensive simulations. We show that we can safely reconstruct the LogN-Log S source distribution of the CDFS down to limiting fluxes of 2.4x10^-17 and 2.1x10^-16 erg s^-1 cm^-2 in the soft (0.5-2 keV) and hard (2-10 keV) bands, respectively, fainter by a factor ~ 2 than current estimates. At these levels we can acco…
We present results from new Chandra and archival HST and VLA imaging observations of the circumnuclear extended emission in the nearby Type 2 Seyfert galaxy NGC 2110. We find resolved soft-band X-ray emission 4'' (~160 pc) north of the nucleus, which is spatially coincident with [OIII] emission, but lies just beyond the northern edge of the radio jet in the source. We find that shock-heating of multi-phase gas clouds can successfully account for this extended emission, although we cannot rule out alternative models, such as the scattering of nuclear radiation by ionized material, or pure photo…
We investigate the optical colours of X-ray sources from the Extended Chandra Deep Field South (ECDFS) using photometry from the COMBO-17 survey, aiming to explore AGN - galaxy feedback models. The X-ray sources populate both the ``blue'' and the ``red sequence'' on the colour-magnitude diagram. However, sources in the ``red sequence'' appear systematically more obscured. HST imaging from the GEMS survey demonstrates that the nucleus does not affect significantly the observed colours, and therefore red sources are early-type systems. In the context of AGN feedback models, this means that there…
We present the optical and infrared identifications of the 266 radio sources detected at 20 cm with the Very Large Array in the Chandra Deep Field South (Kellermann et al. 2008). Using deep i-band Advanced Camera for Surveys, R-band Wide Field Imager, K-band SOFI/NTT, K-band ISAAC/VLT and Spitzer imaging data, we are able to find reliable counterparts for 254 (~95%) VLA sources. Twelve radio sources remain unidentified and three of them are ``empty fields''. Using literature and our own data we are able to assign redshifts to 186 (~70%) radio sources: 108 are spectroscopic redshifts and 78 rel…
The relatively nearby (distance=24.1 Mpc) elliptical galaxy NGC821 hosts an extreme example of a quiescent central massive black hole, for which deep Chandra observations revealed a nuclear source for the first time (with L(2-10 keV)/L_Edd ~ 3.6X10^{-8}). We present here a multiwavelength study of this nucleus, including VLA observations that detect a radio counterpart to the Chandra nuclear source at 1.4 GHz, with a flux density of 127 $μ$m and possibly a flat spectral shape; we also consider new Spitzer IRAC observations and archival HST images. With these data we discuss possible scenarios …
We present Chandra X-ray results for the jet, nucleus, and gaseous atmosphere of NGC 315, a nearby radio galaxy whose jet kinematics are known through deep radio mapping. Diffuse X-ray synchrotron emission is detected from the jet out to 30 arcsec from the nucleus, through regions both of fast bulk flow and deceleration. The X-ray to radio flux ratio drops considerably where the flow decelerates, but the X-ray and radio emissions show similar transverse extents throughout, requiring distributed particle acceleration to maintain the supply of X-ray-emitting electrons. A remarkable knotty filame…
A 96-ks Chandra X-ray observation of rho Ophiuchus cloud core A detected 87 sources, of which 60 were identified with counterparts at other wavelengths. The X-ray detections include 12 of 14 known classical T Tauri stars in the field, 15 of 17 known weak-lined TTS, and 4 of 15 brown dwarf candidates. The X-ray detections are characterized by hard, heavily absorbed emission. The mean photon energy of a typical source is 3 keV, and more than half of the detections are variable. Prominent X-ray flares were detected in the unusual close binary system Oph S1, the X-ray bright WTTS DoAr 21, and the …
We present the results of our spectroscopic follow-up program of the X-ray sources detected in the 942 ks exposure of the Chandra Deep Field South (CDFS). 288 possible counterparts were observed at the VLT with the FORS1/FORS2 spectrographs for 251 of the 349 Chandra sources (including three additional faint X-ray sources). Spectra and R-band images are shown for all the observed sources and R-K colours are given for most of them. Spectroscopic redshifts were obtained for 168 X-ray sources, of which 137 have both reliable optical identification and redshift estimate (including 16 external iden…
In this paper, we provide new 1 Ms $Chandra$ ACIS spectra of two quasars in the Chandra Deep Field South (CDF-S), which were previously reported to show strong and extremely blueshifted X-ray emission/absorption line features in previous 1 Ms spectra, with outflowing bulk velocity $v\sim$0.65-0.84c. In the new 1 Ms spectra, the relativistic blueshifted line feature is solidly confirmed in CXO CDFS J033225.3-274219 (CDFS 46, $z$ = 1.617), and marginally visible in CXO CDFS J033260.0-274748 (CDFS 11, $z$ = 2.579), probably due to the increased Chandra ACIS background in the new 1 Ms exposure. Th…
We present new radio images obtained with the Australia Telescope Compact Array (ATCA) and the Very Large Array (VLA) for a group of 14 galaxies belonging to the 2-Jy sample of radio sources. The new images improve the data already available on these objects and, in general, the database that we are building up on the sample. They will also be used for follow-up work where radio-optical comparison will be done. We briefly discuss the core dominance parameter (R) for the objects for which the new data have given new information and, in particular, for broad line radio galaxies (BLRG). One of th…
We present Chandra point-source catalogs for the Extended Chandra Deep Field-South (E-CDF-S) survey. The E-CDF-S consists of four contiguous 250 ks Chandra observations covering an approximately square region of total solid angle ~0.3 deg^2, which flank the existing ~1 Ms Chandra Deep Field-South (CDF-S). The survey reaches sensitivity limits of 1.1 X 10^-16 erg/cm^2/s and 6.7 X 10^-16 erg/cm^2/s for the 0.5-2.0 keV and 2-8 keV bands, respectively. We detect 762 distinct X-ray point sources within the E-CDF-S exposure; 589 of these sources are new (i.e., not previously detected in the ~1 Ms CD…
We present a detailed analysis of 256 radio sources from our deep (flux density limit of 42 microJy at the field centre at 1.4 GHz) Chandra Deep Field South 1.4 and 5 GHz VLA survey. The radio population is studied by using a wealth of multi-wavelength information in the radio, optical, and X-ray bands. The availability of redshifts for ~ 80% of the sources in our complete sample allows us to derive reliable luminosity estimates for the majority of the objects. X-ray data, including upper limits, for all our sources turn out to be a key factor in establishing the nature of faint radio sources.…
We present the first results of the pure parallel near-UV observations with WFPC2 in the Chandra Deep Field South. The main goal is to search for the population of objects that contribute to the rise in the volume-averaged star formation rate at intermediate redshifts (z<1). A total of 34 objects, were identified in the WFPC2 images and their counterparts found in the ACS GOODS images. We use template fitting of the spectral energy distributions to classify the objects and found that 17 are starbursts, 9 are late-type, 2 are early-type galaxies, and 6 are stars; two of the late-types and one o…
The Extended Chandra Deep Field-South (E-CDF-S) survey consists of 4 Chandra ACIS-I pointings and covers ~1100 square arcminutes (~0.3 deg^2) centered on the original CDF-S field to a depth of approximately 228 ks (PI: Niel Brandt; Lehmer et al, 2005). This is the largest Chandra survey ever conducted at such depth. In our analysis (Virani et al, 2005), we detect 651 unique sources -- 587 using a conservative source detection limit and 64 using a lower source detection limit. Of these 651 sources, 561 are detected in the full 0.5--8.0 keV band, 529 in the soft 0.5--2.0 keV band, and 335 in the…
We present 5, 8, and 15 GHz total intensity and polarimetric observations of the radio source PKS 2322-123 taken with the Very Large Array (VLA). This small (11 kpc) source is located at the center of the cooling-core cluster Abell 2597. The inner X-ray structure, the radio morphology, and the steep spectral index (alpha = -1.8) in the lobes, all suggest that the radio emission is confined by the ambient X-ray gas. We detect a small region of polarized flux in the southern lobe and are able to calculate a Faraday rotation measure (RM) of 3620 rad/m/m over this region. Based on these observatio…
We present first results of our search for high-redshift galaxies in deep CCD mosaic images. As a pilot study for a larger survey, very deep images of the Chandra Deep Field South (CDFS), taken withWFI@MPG/ESO2.2m, are used to select large samples of 1070 U-band and 565 B-band dropouts with the Lyman-break method. The data of these Lyman-break galaxies are made public as an electronic table. These objects are good candidates for galaxies at z~3 and z~4 which is supported by their photometric redshifts. The distributions of apparent magnitudes and the clustering properties of the two population…
We present HST/WFPC2 observations of a well-defined sample of 40 X-ray sources with X-ray fluxes above the detection threshold of the full 1 Msec Chandra Deep Field South (CDFS). The sensitivity and spatial resolution of our HST observations are sufficient to detect the optical counterparts of 37 of the X-ray sources, yielding information on their morphologies and environments. In this paper we extend the results obtained in our previous study on the 300 ks CDFS X-ray data (Schreier et al. 2001, Paper I). Specifically, we show that the optical counterparts to the X-ray sources are divided into…
We present preliminary results from imaging three HST/WFPC2 fields in V and I within the Chandra Deep Field South (CDFS). HST's sensitivity and resolution are sufficient to reveal optical counterparts for 24 of the 26 CDFS X-ray sources detected in the 300 ksec X-ray catalog and to determine the morphologies of most of these. We find that the X-ray sources comprise two apparently distinct populations of optical candidates: one optically faint (I > 24) with V - I colors consistent with the I > 24 field population; the other significantly brighter (I < 22) with colors redder than the I < 22 fiel…
(abridged) We present a detailed reanalysis of the Chandra data for the galaxy cluster Abell 4059 and its central radio galaxy, PKS2354-35. We also present new 1.4GHz and 4.7GHz CnB-array radio data from the Very Large Array (VLA), as well as a short archival WFPC2 image from the Hubble Space Telescope. The presence of a strong interaction between this radio galaxy and the intracluster medium (ICM) was suggested by Huang & Sarazin (1998) on the basis of a short observation by the High Resolution Imager on ROSAT, and confirmed in our preliminary analysis of the Chandra/ACIS-S data. In particula…
Photometric redshifts have proven a powerful tool in identifying galaxies over a large range of lookback times. We have been generalising this technique to incorporate the selection of candidate high redshift QSOs. We have applied this to a large optical/near-infrared imaging survey in 6 wavebands aiming to push farther in redshift (and fainter in luminosity) than previous studies. We believe that study of these very faint and distant objects provides valuable insights into galaxy formation and evolution. Here we present work in progress and preliminary results for a catalogue of objects detec…
We present quantitative morphological analyses of 37 HST/WFPC2 counterparts of X-ray sources in the 1 Ms Chandra Deep Field-South (CDFS). We investigate: 1) 1-D surface brightness profiles via isophotal ellipse fitting; 2) 2-D, PSF- convolved, bulge+disk+nucleus profile-fitting; 3) asymmetry and concentration indices compared with all ~3000 sources in our three WFPC2 fields; and 4) near- neighbor analyses comparing local environments of X-ray sources versus the field control sample. Significant nuclear point-source optical components appear in roughly half of the resolved HST/WFPC2 counterpart…
A large population of heavily obscured, Compton Thick AGNs is predicted by models of galaxy formation, models of Cosmic X-ray Background and by the ``relic'' super-massive black-hole mass function measured from local bulges. However, so far only a handful of Compton thick AGNs have been possibly detected using even the deepest Chandra and XMM surveys. Compton-thick AGNs can be recovered thanks to the reprocessing of the AGN UV emission in the infrared by selecting sources with AGN luminosity's in the mid-infrared and faint near-infrared and optical emission. To this purpose, we make use of dee…
Aims: We study galaxy clustering and explore the dependence of galaxy properties on the the environment up to a redshift z~1, on the basis of a deep multi-band survey in the Chandra Deep Field South. Methods: We have developed a new method which combines galaxy angular positions and photometric redshifts to estimate the local galaxy number-density. This allows both the detection of overdensities in the galaxy distribution and the study of the properties of the galaxy population as a function of the environmental density. Results: We detect two moderate overdensities at z~0.7 and z~1 previously…
We report preliminary results of our H-band survey of the Chandra Deep Field South (CDFS). The observations were made using SofI on the NTT, and cover 0.027 square degrees with a 50% completeness limit of H = 20.5, and 0.17 square degrees with a 50% completeness limit of H =19.8. We used SExtractor to extract sources from our fields. In total we have detected 4819 objects. Star-galaxy separation was performed using the SExtractor parameter ``stellarity index''. All objects with an index of 0.5 or lower were classified as galaxies. According to this criterion, 80 % of our detections are galaxie…
We present the first results of our optical spectroscopy program aimed to provide redshifts and identifications for the X-ray sources in the Extended Chandra Deep Field South. A total of 339 sources were targeted using the IMACS spectrograph at the Magellan telescopes and the VIMOS spectrograph at the VLT. We measured redshifts for 186 X-ray sources, including archival data and a literature search. We find that the AGN host galaxies have on average redder rest-frame optical colors than non-active galaxies, and that they live mostly in the "green valley". The dependence of the fraction of AGN t…
We studied the morphology of galaxies in the Chandra Deep Field South using ACS multi-wavelength data from the Great Observatories Origin Deep Survey and 524 spectroscopic redshifts from the VIMOS VLT Deep Survey completed with 2874 photometric redshift computed from COMBO-17 multi-color data. The rest-frame B-band makes it possible to discriminate two morphological types in an asymmetry-concentration diagram: bulge- and disk-dominated galaxies. The rest-frame color index $B-I$ is found to be very correlated with the morphological classification: wholly bulge-dominated galaxies are redder than…
This paper presents multi-passband optical data obtained from observations of the Chandra Deep Field South (CDF-S), located at alpha ~ 3h 32m, delta ~ -27d 48m. The observations were conducted at the ESO/MPG 2.2m telescope at La Silla using the 8kx8k Wide-Field Imager (WFI). This data set, taken over a period of one year, represents the first field to be completed by the ongoing Deep Public Survey (DPS) being carried out by the ESO Imaging Survey (EIS) project. This paper describes the optical observations, the techniques employed for un-supervised pipeline processing and the general character…
We present results from 300 ks of X-ray observations of the Chandra Deep Field South. The field of the four combined exposures is now 0.1035 deg^2 and we reach a flux limit of 10^{-16} erg s^{-1} cm^{-2} in the 0.5-2 keV soft band and 10^{-15} erg s^{-1} cm^{-2} in the 2-10 keV hard band, thus a factor 2 fainter than the previous 120 ks exposure. The total catalogue is composed of 197 sources including 22 sources detected only in the hard band, 51 only in the soft band, and 124 detected in both bands. We have now the optical spectra for 86 optical counterparts. We compute the total contributio…
In this Paper we present the source catalog obtained from a 942 ks exposure of the Chandra Deep Field South (CDFS), using ACIS-I on the Chandra X-ray Observatory. Catalog generation proceeded simultaneously using two different methods; a method of our own design using a modified version of the SExtractor algorithm, and a wavelet transform technique developed specifically for Chandra observations. The detection threshold has been set in order to have less than 10 spurious sources, as assessed by extensive simulations. We subdivided the catalog into four sections. The primary list consists of ob…
We present near-IR (J and Ks) number counts and colors of galaxies detected in deep VLT-ISAAC images centered on the Chandra Deep Field and Hubble Deep Field-South for a total area of 13.6 arcmin$^2$. The limiting surface brightness obtained is Ks$\simeq$22.8 mag/arcsec$^2$ and J$\simeq$24.5 (1$σ$) on both fields. A d$log$N/dm relation with a slope of $\sim0.34$ in J and $\sim0.28$ in Ks is found in both fields with no evidence of decline near the magnitude limit. The median J-Ks color of galaxies becomes bluer at magnitudes fainter than Ks$\sim18$, in agreement with the different number count…
In this letter we report the detection of an extremely strong X-ray emission line in the 940ks chandra ACIS-I spectrum of CXO CDFS J033225.3-274219. The source was identified as a Type1 AGN at redshift of z = 1.617, with 2.0 -- 10.0 keV rest frame X-ray luminosity of ~ 10^44 ergs s^-1. The emission line was detected at 6.2^{+0.2}_{-0.1} keV, with an equivalent width (EW) of 4.4^{+3.2}_{-1.4} keV, both quantities referring to the observed frame. In the rest frame, the line is at 16.2^{+0.4}_{-0.3} keV with an EW of 11.5^{+8.3}_{-3.7} keV. An X-ray emission line at similar energy (~ 17 keV, rest…
We provide important new constraints on the nature and redshift distribution of optically faint (R>25) X-ray sources in the Chandra Deep Field South Survey. We show that we can derive accurate photometric redshifts for the spectroscopically unidentified sources thus maximizing the redshift completeness for the whole X-ray sample. Our new redshift distribution for the X-ray source population is in better agreement with that predicted by X-ray background synthesis models; however, we still find an overdensity of low redshift (z<1) sources. The optically faint sources are mainly X-ray absorbed AG…
We studied the X-ray variability of sources detected in the Chandra Deep Field South (Giacconi et al. 2002), nearly all of which are low to moderate z AGN (Tozzi et al. 2001). We find that 45% of the sources with >100 counts exhibit significant variability on timescales ranging from a day up to a year. The fraction of sources found to be variable increases with observed flux, suggesting that >90% of all AGNs possess intrinsic variability. We also find that the fraction of variable sources appears to decrease with increasing intrinsic absorption; a lack of variability in hard, absorbed AGNs cou…
We present first results of the X-ray spectral analysis of the 500 ksec deep survey obtained with XMM-Newton on the Chandra Deep Field South (CDFS). Statistical distributions of spectral index and intrinsic absorption are derived for a sample containing 70 sources with a count limit of 100 (flux limit in the [2-10] keV band of 8.9 $\times 10^{-16}$ erg cm$^{-2}$ s$^{-1}$), of which 44 have redshift identification. We observe a separation between the type-1 and the type-2 AGN in diagnostics involving different X-ray parameters. Using the subsample with known $z$, we show that this separation be…
The Extended Chandra Deep Field-South (ECDFS) survey consists of 4 Chandra ACIS-I pointings and covers $\approx$ 1100 square arcminutes ($\approx$ 0.3 deg$^2$) centered on the original CDF-S field to a depth of approximately 228 ks. This is the largest Chandra survey ever conducted at such depth, and only one XMM-Newton survey reaches a lower flux limit in the hard 2.0--8.0 keV band. We detect 651 unique sources -- 587 using a conservative source detection threshold and 64 using a lower source detection threshold. These are presented as two separate catalogs. Of the 651 total sources, 561 are …
We present an analysis of a highly asymmetric cluster merger from a Chandra observation of Abell 85. The merger shows significant disruption of the less massive subcluster from ram pressure effects. Nevertheless, a cold core, coincident with the cD galaxy, is observed to persist in the subcluster. We derive dynamical information from the motion of the cold core through the main cluster's ICM. Multiple derivations of the velocity of the core suggest a Mach number of M ~ 1.4 or v ~ 2150 km/s, though with substantial uncertainty. We construct a consistent kinematic model for the merger based on t…
Sgr A*, the massive black hole at the center of the Galaxy, varies in radio through X-ray emission on hourly time scales. The flare activity is thought to arise from the innermost region of an accretion flow onto Sgr A*. We present simultaneous light curves of Sgr A* in radio, sub-mm and X-rays that show a possible time delay of 110$\pm17$ minutes between X-ray and 850 $μ$m suggesting that the sub-mm flare emission is optically thick. At radio wavelengths, we detect time lags of of $20.4\pm6.8, 30\pm12$ and 20$\pm6$ minutes between the flare peaks observed at 13 and 7 mm (22 and 43 GHz) in thr…
We have combined multi-wavelength observations of a selected sample of starforming galaxies with galaxy evolution models in order to compare the results obtained for different SFR tracers and to study the effect that the evolution of the starforming regions has on them. We also aimed at obtaining a better understanding of the corrections due to extinction and nuclear activity on the derivation of the SFR. We selected the sample from Chandra data for the well studied region Chandra Deep Field South (CDFS) and chose the objects that also have UV and IR data from GALEX and GOODS-Spitzer respectiv…
The HEGRA Cherenkov telescope array group recently reported a steady and extended unidentified TeV gamma-ray source lying at the outskirts of Cygnus OB2. This is the most massive stellar association known in the Galaxy, estimated to contain ~2600 OB type members alone. It has been previously argued that the large scale shocks and turbulence induced by the multiple interacting supersonic winds from the many young stars in such associations may play a role in accelerating Galactic cosmic rays. Indeed, Cyg OB2 also coincides with the non-variable MeV-GeV range unidentified EGRET source, 3EG 2033+…
{This paper presents the VIMOS VLT Deep Survey around the Chandra Deep Field South (CDFS). We have measured 1599 new redshifts with VIMOS on the European Observatory Very Large Telescope - UT3, in an area 21x21.6 arcmin^2, including 784 redshifts in the Hubble Space Telescope - Advanced Camera for Surveys GOODS area. 30% of all objects with I_AB=24 have been observed independently of magnitude, indicating that the sample is purely magnitude limited. We have reached an unprecedented completeness level of 88% in terms of the ratio of secure measurements vs. observed objects, while 95% of all obj…
We present point-source catalogs for the ~2 Ms exposure of the Chandra Deep Field-South (CDF-S); this is one of the two most-sensitive X-ray surveys ever performed. The survey covers an area of ~436 arcmin^2 and reaches on-axis sensitivity limits of ~1.9x10^{-17} and ~1.3x10^{-16} ergs/cm^2/s for the 0.5-2.0 and 2-8 keV bands, respectively. Four hundred and sixty-two X-ray point sources are detected in at least one of three X-ray bands that were searched; 135 of these sources are new compared to the previous ~1 Ms CDF-S detections. Source positions are determined using centroid and matched-fil…
This paper presents new J and Ks near-infrared data obtained from observations of the Chandra Deep Field South (CDF-S) conducted at the ESO 3.5m New Technology Telescope (NTT). These data were taken as part of the ongoing Deep Public Survey (DPS) being carried out by the ESO Imaging Survey (EIS) program, extending the EIS-DEEP survey. Combined these surveys now provide a contiguous coverage over an area of 400 square arcmin in the near-infrared, nearly matching that covered by the deep X-ray observations of Chandra, four times the area of the original EIS-DEEP survey. The paper briefly describ…
(abridged) Stellar catalogues in five passbands (UBVRI) over an area of approximately 0.3 deg^2, comprising about 1200 objects, and in seven passbands (UBVRIJK) over approximately 0.1 deg^2, comprising about 400 objects, in the direction of the Chandra Deep Field South are presented. The 90% completeness level of the number counts is reached at approximately U = 23.8, B = 24.0, V = 23.5, R = 23.0, I = 21.0, J = 20.5, K = 19.0. A scheme is presented to select point sources from these catalogues, by combining the SExtractor parameter CLASS_STAR from all available passbands. Probable QSOs and unr…
Variability is a property shared by virtually all active galactic nuclei (AGNs), and was adopted as a criterion for their selection using data from multi epoch surveys. Low Luminosity AGNs (LLAGNs) are contaminated by the light of their host galaxies, and cannot therefore be detected by the usual colour techniques. For this reason, their evolution in cosmic time is poorly known. Consistency with the evolution derived from X-ray detected samples has not been clearly established so far, also because the low luminosity population consists of a mixture of different object types. LLAGNs can be dete…
We present the COMBO-17 object catalogue of the Chandra Deep Field South for public use, covering a field which is 31.5' x 30' in size. This catalogue lists astrometry, photometry in 17 passbands from 350 to 930 nm, and ground-based morphological data for 63,501 objects. The catalogue also contains multi-colour classification into the categories 'Star', 'Galaxy' and 'Quasar' as well as photometric redshifts. We include restframe luminosities in Johnson, SDSS and Bessell passbands and estimated errors. The redshifts are most reliable at R<24, where the sample contains approximately 100 quasars,…
We present a detailed X-ray spectral analysis of the sources in the 1Ms catalog of the Chandra Deep Field South (CDFS) taking advantage of optical spectroscopy and photometric redshifts for 321 sources. As a default spectral model, we adopt a power law with slope Gamma with an intrinsic redshifted absorption N_H, a fixed Galactic absorption and an unresolved Fe emission line. For 82 X-ray bright sources, we perform the X-ray spectral analysis leaving both Gamma and N_H free. The weighted mean value is <Gamma>~ 1.75+-0.02, with an intrinsic dispersion of sigma~0.30. We do not find hints of a co…
Our VLA observations of the XMM-Newton/Chandra 13hr deep survey field (see Page et al., this proceedings) result in one of the two deepest 1.4GHz radio maps ever made. Within the 15' radius field covered by the deep X-ray data (0.19 sq deg), a total of 556 radio sources are detected, down to a 4 sigma flux limit of 28uJy. Of the 214 Chandra sources, 55 have radio counterparts. The sub-arcsecond accuracy of the VLA and Chandra positions enable us to determine with high confidence the sources common to both surveys. Here we present the relationship between the X-ray and radio source populations …
We describe the results of an extremely deep, 0.28 deg^2 survey for z = 3.1 Ly-alpha emission-line galaxies in the Extended Chandra Deep Field South. By using a narrow-band 5000 Anstrom filter and complementary broadband photometry from the MUSYC survey, we identify a statistically complete sample of 162 galaxies with monochromatic fluxes brighter than 1.5 x 10^-17 ergs cm^-2 s^-1 and observers frame equivalent widths greater than 80 Angstroms. We show that the equivalent width distribution of these objects follows an exponential with a rest-frame scale length of w_0 = 76 +/- 10 Angstroms. In …
We report on Chandra imaging observations of the Galactic Unidentified $γ$-ray source GEV J1809-2327, comparing the X-ray images with new VLA 1.46 GHz and 4.86 GHz maps. The X-ray images reveal a point source connected to a non-thermal X-ray/radio nebula, supporting a pulsar/wind model for the $γ$-ray emitter. We also detect numerous X-ray sources from the young stellar association in the adjacent HII region S32.
We investigate the evolution over the last 6.3 Gyr of cosmic time (i.e., since z ~ 0.7) of the average X-ray properties of early-type galaxies within the Extended Chandra Deep Field-South (E-CDF-S). Our early-type galaxy sample includes 539 objects with red-sequence colors and Sersic indices larger than n = 2.5, which were selected jointly from the COMBO-17 (Classifying Objects by Medium-Band Observations in 17 Filters) and GEMS (Galaxy Evolution from Morphologies and SEDs) surveys. We utilize the deep Chandra observations over the E-CDF-S and X-ray stacking analyses to constrain primarily the…
We report 20 and 6 cm VLA deep observations of the CDF-S including the Extended CDF-S. We discuss the radio properties of 266 cataloged radio sources, of which 198 are above a 20 cm completeness level reaching down to 43 microJy at the center of the field. Survey observations made at 6 cm over a more limited region covers the original CDF-S to a comparable level of sensitivity as the 20 cm observations. Of 266 cataloged radio sources, 52 have X-ray counterparts in the CDF-S and a further 37 in the E-CDF-S area not covered by the 1 Megasecond exposure. Using a wide range of material, we have fo…
We present the main results from our 940 ksec observation of the Chandra Deep Field South (CDFS), using the source catalog described in an accompanying paper (Giacconi et al. 2001). We extend the measurement of source number counts to 5.5e-17 erg/cm^2/s in the soft 0.5-2 keV band and 4.5e-16 erg/cm^2/s in the hard 2-10 keV band. The hard band LogN-LogS shows a significant flattening (slope~=0.6) below ~1e-14 erg/cm^2/s, leaving at most 10-15% of the X-ray background (XRB) to be resolved, the main uncertainty lying in the measurement of the total flux of the XRB. On the other hand, the analysis…
In this paper we present preliminary spectroscopic results from a small area faint K-excess (KX) survey, and compare KX selection against UVX selection. The aim of the KX method is to produce complete samples of QSOs flux-limited in the K band, in order to minimize any selection bias in samples of QSOs from the effects of reddening and extinction. Using the photometric catalogue of the ESO Imaging Survey Chandra Deep Field South (48 arcmin^2) we have identified compact objects with J-K colours redder than the stellar sequence, that are brighter than K=19.5. We have obtained spectra of 33 candi…
We report the discovery of a luminous z=5.78 star-forming galaxy in the Chandra Deep Field South. This galaxy was selected as an `i-drop' from the GOODS public survey imaging with HST/ACS (object 3 in Stanway, Bunker & McMahon 2003, astro-ph/0302212). The large colour of (i'-z')_AB=1.6 indicated a spectral break consistent with the Lyman-alpha forest absorption short-ward of Lyman-alpha at z~6. The galaxy is very compact (marginally resolved with ACS with a half-light radius of 0.08arcsec, so r_hl<0.5kpc/h_70). We have obtained a deep (5.5-hour) spectrum of this z'(AB)=24.7 galaxy with the DEI…
We present the Chandra results of AX J1843.8-0352, a supernova remnant (SNR) recently identified with ASCA. Chandra spatially resolved two components from this SNR: non-thermal and thermal ones. The morphology of the non-thermal component is clumpy and elliptical, elongated from the north to the south with a mean diameter of about 9 arcmin. The spectrum is fitted with a power-law model of photon index 2.1 and the east rim is associated with the non-thermal radio sources C and F (Helfand et al. 1989). Therefore the non-thermal component is probably synchrotron X-rays by energetic electrons acce…
We investigate the spatial clustering of X-ray selected sources in the two deepest X-ray fields to date, namely the 2Msec Chandra Deep Field North (CDFN) and the 1Msec Chandra Deep Field South (CDFS). The projected correlation function w(r_p), measured on scales ~0.2-10 h^-1 Mpc for a sample of 240 sources with spectroscopic redshift in the CDFN and 124 sources in the CDFS at a median redshift of z~0.8, is used to constrain the amplitude and slope of the real space correlation function xi(r)=(r/r0)^-gamma. The clustering signal is detected at high confidence (>~ 7 sigma) in both fields. The am…
Based on the photometry of 10 near-UV, optical, and near-infrared bands of the Chandra Deep Field South, we estimate the photometric redshifts for 342 X-ray sources, which constitute ~99% of all the detected X-ray sources in the field. The models of spectral energy distribution are based on galaxies and a combination of power-law continuum and emission lines. Color information is useful for source classifications: Type-I AGN show non-thermal spectral features that are distinctive from galaxies and Type-II AGN. The hardness ratio in X-ray and the X-ray-to-optical flux ratio are also useful disc…
