scholarly journals GOODS-ALMA: 1.1 mm galaxy survey

2018 ◽  
Vol 620 ◽  
pp. A152 ◽  
Author(s):  
M. Franco ◽  
D. Elbaz ◽  
M. Béthermin ◽  
B. Magnelli ◽  
C. Schreiber ◽  
...  
Keyword(s):  
Near Infrared ◽  
Detection Algorithm ◽  
Point Sources ◽  
Blind Detection ◽  
Expected Number ◽  
Photometric Redshifts ◽  
Mid Infrared ◽  
X Ray ◽  
Massive Galaxies ◽  
Number Counts

Aims. We present a 69 arcmin2 ALMA survey at 1.1 mm, GOODS-ALMA, matching the deepest HST-WFC3 H-band part of the GOODS-South field. Methods. We tapered the 0″24 original image with a homogeneous and circular synthesized beam of 0″60 to reduce the number of independent beams – thus reducing the number of purely statistical spurious detections – and optimize the sensitivity to point sources. We extracted a catalog of galaxies purely selected by ALMA and identified sources with and without HST counterparts down to a 5σ limiting depth of H = 28.2 AB (HST/WFC3 F160W). Results. ALMA detects 20 sources brighter than 0.7 mJy at 1.1 mm in the 0″60 tapered mosaic (rms sensitivity σ ≃ 0.18 mJy beam−1) with a purity greater than 80%. Among these detections, we identify three sources with no HST nor Spitzer-IRAC counterpart, consistent with the expected number of spurious galaxies from the analysis of the inverted image; their definitive status will require additional investigation. We detect additional three sources with HST counterparts either at high significance in the higher resolution map, or with different detection-algorithm parameters ensuring a purity greater than 80%. Hence we identify in total 20 robust detections. Conclusions. Our wide contiguous survey allows us to push further in redshift the blind detection of massive galaxies with ALMA with a median redshift of z = 2.92 and a median stellar mass of M⋆ = 1.1 × 1011 M⊙. Our sample includes 20% HST-dark galaxies (4 out of 20), all detected in the mid-infrared with Spitzer-IRAC. The near-infrared based photometric redshifts of two of them (z ∼ 4.3 and 4.8) suggest that these sources have redshifts z >  4. At least 40% of the ALMA sources host an X-ray AGN, compared to ∼14% for other galaxies of similar mass and redshift. The wide area of our ALMA survey provides lower values at the bright end of number counts than single-dish telescopes affected by confusion.

scholarly journals X-Ray and Near-Infrared Spectroscopy of Dim X-Ray Point Sources Constituting the Galactic Ridge X-Ray Emission

2014 ◽  
Vol 1 (1) ◽  
pp. 222-226
Author(s):  
Kumiko Morihana ◽  
Masahiro Tsujimoto ◽  
Ken Ebisawa
Keyword(s):  
Near Infrared ◽  
Cataclysmic Variables ◽  
Point Sources ◽  
X Ray ◽  
Nir Imaging ◽  
Group A ◽  
Field L ◽  
Imaging And Spectroscopy ◽  
Group B ◽  
Thermal Sources

We present the results of X-ray and Near-Infrared observations of the Galactic Ridge X-ray Emission (GRXE). We extracted 2,002 X-ray point sources in the <em>Chandra</em> Bulge Field (l =0°.113, b = 1°.424) down to ~10<sup>-14.8</sup> ergscm<sup>-2</sup>s<sup>-1</sup> in 2-8 keV band with the longest observation (900 ks) of the GRXE. Based on X-ray brightness and hardness, we classied the X-ray point sources into three groups: A (hard), B (soft and broad spectrum), and C (soft and peaked spectrum). In order to know populations of the X-ray point sources, we carried out NIR imaging and spectroscopy observation. We identied 11% of X-ray point sources with NIR and extracted NIR spectra for some of them. Based on X-ray and NIR properties, we concluded that non-thermal sources in the group A are mostly active galactic nuclei and the thermal sources are mostly white dwarf binaries such as cataclysmic variables (CVs) and Pre-CVs. We concluded that the group B and C sources are X-ray active stars in flare and quiescence, respectively.

scholarly journals Mid-infrared and X-ray luminosity correlations of X-ray point sources in NGC 1399

2013 ◽  
Vol 434 (1) ◽  
pp. 639-651 ◽  
Author(s):  
P. Shalima ◽  
V. Jithesh ◽  
K. Jeena ◽  
R. Misra ◽  
S. Ravindranath ◽  
...  
Keyword(s):  
Point Sources ◽  
Mid Infrared ◽  
X Ray

scholarly journals Near-infrared spectroscopy of faint discrete X-ray point sources constituting the Galactic ridge X-ray emission

2016 ◽  
Vol 68 (4) ◽  
pp. 57 ◽  
Author(s):  
Kumiko Morihana ◽  
Masahiro Tsujimoto ◽  
Pierre Dubath ◽  
Tessei Yoshida ◽  
Kensuke Suzuki ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Point Sources ◽  
X Ray

scholarly journals Identification of AGN in the XMM-Newton X-ray survey of the SMC

2019 ◽  
Vol 622 ◽  
pp. A29 ◽  
Author(s):  
Chandreyee Maitra ◽  
Frank Haberl ◽  
Valentin D. Ivanov ◽  
Maria-Rosa L. Cioni ◽  
Jacco Th. van Loon
Keyword(s):  
Near Infrared ◽  
Spectral Characteristics ◽  
Selection Criterion ◽  
Galactic Nuclei ◽  
Seyfert Galaxies ◽  
Mid Infrared ◽  
X Ray ◽  
Stellar Density ◽  
Narrow Emission

Context. Finding active galactic nuclei (AGN) behind the Magellanic Clouds (MCs) is difficult because of the high stellar density in these fields. Although the first AGN behind the Small Magellanic Cloud (SMC) were reported in the 1980s, it is only recently that the number of AGN known behind the SMC has increased by several orders of magnitude. Aims. The mid-infrared colour selection technique has proven to be an efficient means of identifying AGN, especially obscured sources. The X-ray regime is complementary in this regard and we use XMM-Newton observations to support the identification of AGN behind the SMC. Methods. We present a catalogue of AGN behind the SMC by correlating an updated X-ray point-source catalogue from our XMM-Newton survey of the SMC with previously identified AGN from the literature as well as a list of candidates obtained from the ALLWISE mid-infrared colour-selection criterion. We studied the properties of the sample with respect to their redshifts, luminosities, and X-ray spectral characteristics. We also identified the near-infrared counterpart of the sources from the VISTA observations. Results. The redshift and luminosity distributions of the sample (where known) indicate that we detect sources ranging from nearby Seyfert galaxies to distant and obscured quasars. The X-ray hardness ratios are compatible with those typically expected for AGN, and the VISTA colours and variability are also consistent with AGN. A positive correlation was observed between the integrated X-ray flux (0.2–12 keV) and the ALLWISE and VISTA magnitudes. We further present a sample of new candidate AGN and candidates for obscured AGN. Together these make an interesting subset for further follow-up studies. An initial spectroscopic follow-up of 6 out of the 81 new candidates showed that all six sources are active galaxies, although two have narrow emission lines.

scholarly journals GOODS-ALMA: Optically dark ALMA galaxies shed light on a cluster in formation at z = 3.5

2020 ◽  
Vol 642 ◽  
pp. A155 ◽  
Author(s):  
L. Zhou ◽  
D. Elbaz ◽  
M. Franco ◽  
B. Magnelli ◽  
C. Schreiber ◽  
...  
Keyword(s):  
Near Infrared ◽  
Far Infrared ◽  
Spectral Energy ◽  
Photometric Redshifts ◽  
Cluster Galaxy ◽  
Massive Galaxies ◽  
The Galaxy ◽  
Infrared Spectral ◽  
Shed Light

Thanks to its outstanding angular resolution, the Atacama Large Millimeter/submillimeter Array (ALMA) has recently unambiguously identified a population of optically dark galaxies with redshifts greater than z = 3, which play an important role in the cosmic star formation in massive galaxies. In this paper we study the properties of the six optically dark galaxies detected in the 69 arcmin2 GOODS-ALMA 1.1 mm continuum survey. While none of them are listed in the deepest H-band based CANDELS catalog in the GOODS-South field down to H = 28.16 AB, we were able to de-blend two of them from their bright neighbor and measure an H-band flux for them. We present the spectroscopic scan follow-up of five of the six sources with ALMA band 4. All are detected in the 2 mm continuum with signal-to-noise ratios higher than eight. One emission line is detected in AGS4 (νobs = 151.44 GHz with an S/N = 8.58) and AGS17 (νobs = 154.78 GHz with an S/N = 10.23), which we interpret in both cases as being due to the CO(6–5) line at zspecAGS4 = 3.556 and zspecAGS17 = 3.467, respectively. These redshifts match both the probability distribution of the photometric redshifts derived from the UV to near-infrared spectral energy distributions (SEDs) and the far-infrared SEDs for typical dust temperatures of galaxies at these redshifts. We present evidence that nearly 70% (4/6 of galaxies) of the optically dark galaxies belong to the same overdensity of galaxies at z ∼ 3.5. overdensity The most massive one, AGS24 (M⋆ = 1011.32−0.19+0.02 M⊙), is the most massive galaxy without an active galactic nucleus at z > 3 in the GOODS-ALMA field. It falls in the very center of the peak of the galaxy surface density, which suggests that the surrounding overdensity is a proto-cluster in the process of virialization and that AGS24 is the candidate progenitor of the future brightest cluster galaxy.

scholarly journals Broad view on hard X-ray background emission of the Galaxy

2009 ◽  
Vol 5 (H15) ◽  
pp. 810-810
Author(s):  
Roman Krivonos ◽  
Mikhail Revnivtsev ◽  
Sergey Tsygankov ◽  
Eugene Churazov ◽  
Rashid Sunyaev
Keyword(s):  
Near Infrared ◽  
Galactic Disk ◽  
Broad Band ◽  
Point Sources ◽  
X Rays ◽  
X Ray ◽  
Scientific Debate ◽  
The Galaxy ◽  
Background Emission ◽  
Galactic Background

AbstractThe nature of the Galactic Ridge X-Ray Emission (GRXE) has been under scientific debate since its discovery more than 30 years ago. It is observed as extended emission along the Galactic disk. The question was: is GRXE truly diffuse or is it composed from a large number of unresolved point sources? Using near-infrared Galaxy maps measured with the DIRBE experiment and data from the INTEGRAL observatory, we show that the galactic background in the energy range 20-60 keV originates from the stellar population of the Galaxy, which is in contrast to the diffuse nature believed before (Krivonos et al., 2007). Here we show preliminary results of studying the transition region from hard X-rays to gamma diffuse background of the Galaxy, revealing the broad band picture of Galactic Background emission.

scholarly journals The massive star-forming region Cygnus OB2

2009 ◽  
Vol 5 (S266) ◽  
pp. 551-554
Author(s):  
N. J. Wright ◽  
J. J. Drake
Keyword(s):  
Massive Star ◽  
Near Infrared ◽  
Protoplanetary Disks ◽  
Mass Function ◽  
Initial Mass Function ◽  
Point Sources ◽  
Older Population ◽  
X Ray ◽  
Ob Stars ◽  
Star Forming

AbstractWe present results from a catalogue of 1696 X-ray point sources detected in the massive star-forming region Cygnus OB2, the majority of which have optical or near-infrared associations. We derive ages of 3.5 and 5.25 Myr for the stellar populations in our two fields, in agreement with recent studies that suggest that the central 1–3 Myr-old OB association is surrounded and contaminated by an older population with an age of 5–10 Myr. The fraction of sources with protoplanetary disks, as traced by K-band excesses, is unusually low. Although this has previously been interpreted as due to the influence of the large number of OB stars in Cyg OB2, contamination from an older population of stars in the region could also be responsible. An initial mass function is derived and found to have a slope of Γ = −1.27, in agreement with the canonical value. Finally, we introduce the recently approved Chandra Cygnus OB2 Legacy Survey that will image a 1 square degree area of the Cygnus OB2 association to a depth of 120~ks, likely detecting ~ 10 000 stellar X-ray sources.

scholarly journals Nature versus nurture: relic nature and environment of the most massive passive galaxies at z < 0.5

2020 ◽  
Vol 638 ◽  
pp. L11 ◽  
Author(s):  
C. Tortora ◽  
N. R. Napolitano ◽  
M. Radovich ◽  
C. Spiniello ◽  
L. Hunt ◽  
...  
Keyword(s):  
Star Formation ◽  
Galaxy Formation ◽  
Near Infrared ◽  
Early Stage ◽  
High Redshift ◽  
Global Environment ◽  
Massive Galaxies ◽  
Size Growth ◽  
Stellar Masses ◽  
Number Counts

Relic galaxies are thought to be the progenitors of high-redshift red nuggets that for some reason missed the channels of size growth and evolved passively and undisturbed since the first star formation burst (at z >  2). These local ultracompact old galaxies are unique laboratories for studying the star formation processes at high redshift and thus the early stage of galaxy formation scenarios. Counterintuitively, theoretical and observational studies indicate that relics are more common in denser environments, where merging events predominate. To verify this scenario, we compared the number counts of a sample of ultracompact massive galaxies (UCMGS) selected within the third data release of the Kilo Degree Survey, that is, systems with sizes Re <  1.5 kpc and stellar masses M⋆ >  8 × 1010 M⊙, with the number counts of galaxies with the same masses but normal sizes in field and cluster environments. Based on their optical and near-infrared colors, these UCMGS are likely to be mainly old, and hence representative of the relic population. We find that both UCMGS and normal-size galaxies are more abundant in clusters and their relative fraction depends only mildly on the global environment, with denser environments penalizing the survival of relics. Hence, UCMGS (and likely relics overall) are not special because of the environment effect on their nurture, but rather they are just a product of the stochasticity of the merging processes regardless of the global environment in which they live.

scholarly journals Triggering nuclear and galaxy activity in the Bullet cluster

2020 ◽  
Vol 634 ◽  
pp. A137
Author(s):  
S. Puccetti ◽  
F. Fiore ◽  
A. Bongiorno ◽  
K. Boutsia ◽  
R. Fassbender ◽  
...  
Keyword(s):  
Infrared Emission ◽  
Point Sources ◽  
Photometric Redshifts ◽  
X Ray ◽  
Cluster Galaxies ◽  
Star Forming ◽  
Multi Wavelength ◽  
Cluster Environment ◽  
Infrared Sources ◽  
Trigger Mechanisms

The analysis of a cluster environment is a valuable instrument to investigate the origin of gas fuelling and trigger mechanisms in active galactic nuclei (AGN) and star-forming galaxies. To this purpose, we present a detailed analysis of the point-like X-ray sources in the Bullet cluster field. Based on ∼600 ks Chandra observations, we produced a catalogue of 381 X-ray point sources up to a distance of ∼1.5 virial radius and with flux limits ∼1 × 10−16 and ∼8 × 10−16 erg cm−2 s−1 in the 0.5–2 keV and 2–10 keV bands, respectively. We find a strong (up to a factor 1.5–2) and significant (≥4σ) over-density in the full region studied 0.3R200 <  R <  1.5R200. We identified optical (R band) and infrared (Spitzer IRAC) counterparts for ∼84% and ∼48% of the X-ray sources, respectively. We obtained new spectroscopic redshifts for 106 X-ray sources and collected from the literature additional 13 spectroscopic and 8 photometric redshifts of X-ray sources. Twenty-nine X-ray sources turned out to be cluster members. Spectroscopic and photometric redshifts of optical and infrared sources were also collected, and these sources were used as ancillary samples. We used these multi-wavelength data to characterise the nature of the Bullet cluster X-ray point sources. We find that the over-density in the region 0.3R200 <  R <  R200 is likely due to X-ray AGN (mostly obscured) and star-forming galaxies associated with the cluster, while in the more external region this over-density is likely to be mostly due to background AGN. The fraction of cluster galaxies hosting an X-ray detected AGN is 1.0 ± 0.4%, which is nearly constant with the radius; this fraction is similar to that reported in other clusters of galaxies at similar redshift. The fraction of X-ray bright AGN (L2 − 10 keV >  1043 ergs s−1) in the region 0.3R200 <  R <  R200 is 0.5−0.2+0.6%, which is higher than that in other clusters at similar redshift and more similar to the AGN fraction in the field. Finally, the spatial distributions of AGN and star-forming galaxies, which we selected for their infrared emission, appear similar, thus suggesting that both are triggered by the same mechanism.

scholarly journals The Diffuse Near- and Mid-Infrared Emission from the Galaxy

2001 ◽  
Vol 204 ◽  
pp. 35-46
Author(s):  
Martin Cohen
Keyword(s):  
Point Source ◽  
Surface Brightness ◽  
Near Infrared ◽  
Infrared Emission ◽  
Point Sources ◽  
Mid Infrared ◽  
Deep Point ◽  
Model Predictions ◽  
The Galaxy ◽  
Fundamental Stellar Parameters

Recognition of an isotropic cosmic near-infrared (NIR) and mid-infrared (MIR) background involves the removal of the zodiacal foreground (both scattered and reradiated), of the truly diffuse Galactic foreground (dominated by fluorescent bands of polcyclic aromatic hydrocarbons), and of resolved and unresolved Galactic point sources. I discuss model simulations of the near- and mid-infrared point source sky from which one can assess its particular contribution to the diffuse Galactic infrared foreground. I will also indicate the transitional stage which characterizes our knowledge of fundamental stellar parameters that are essential inputs to any such models. Using the latest version of the SKY model (Wainscoat et al. 1992; Cohen 1993; Cohen 1994; Cohen et al. 1994; Cohen 1995; Ruphy et al. 1997), I will demonstrate matches to deep point source counts for a variety of passbands and galactic latitudes, and will try to quantify the uncertainties achievable in model predictions of the integrated surface brightness due to the smearing of all these foreground point sources.

Sign in / Sign up

Export Citation Format

Share Document