Confirmation of a galaxy cluster hidden behind the Galactic bulge using the VVV survey

Coldwell, Georgina; Alonso, Santiago; Duplancic, Fernanda; Hempel, M.; Ivanov, V. D.; Minniti, D.

doi:10.1051/0004-6361/201423464

Cited by 20 publications

(27 citation statements)

References 48 publications

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“…Other X-ray detections were obtained by Lopes de Oliveira et al (2006), who discovered Cl 2334+48 at z = 0.271 in the Zone of Avoidance in the XMM-Newton archive, and by Mori et al (2013), who detected the rich cluster Suzaku J1759-3450 at z = 0.13 behind the Milky Way bulge. The latter cluster was then confirmed by Coldwell et al (2014), based on infrared data. ered in X-rays by Johnston et al (1981), who identified the 4U 1708 − 23 X-ray source with a cluster of galaxies, and more or less simultaneously at optical wavelengths by Wakamatsu & Malkan (1981) during a search for highly absorbed Galactic globular clusters.…”

Section: Introductionmentioning

confidence: 68%

Ophiuchus: An optical view of a very massive cluster of galaxies hidden behind the Milky Way

Durret

Wakamatsu

Nagayama

et al. 2015

A&A

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Context. The Ophiuchus cluster, at a redshift z = 0.0296, is known from X-rays to be one of the most massive nearby clusters, but its optical properties have not been investigated in detail because of its very low Galactic latitude. Aims. We discuss the optical properties of the galaxies in the Ophiuchus cluster, in particular, with the aim of understanding its dynamical properties better. Methods. We have obtained deep optical imaging in several bands with various telescopes, and applied a sophisticated method to model and subtract the contributions of stars to measure galaxy magnitudes as accurately as possible. The colour−magnitude relations obtained show that there are hardly any blue galaxies in Ophiuchus (at least brighter than r ≤ 19.5), and this is confirmed by the fact that we only detect two galaxies in Hα. We also obtained a number of spectra with ESO-FORS2, which we combined with previously available redshifts. Altogether, we have 152 galaxies with spectroscopic redshifts in the 0.02 ≤ z ≤ 0.04 range, and 89 galaxies with both a redshift within the cluster redshift range and a measured r band magnitude (limited to the Megacam 1 × 1 deg 2 field). Results. A complete dynamical analysis based on the galaxy redshifts available shows that the overall cluster is relaxed and has a mass of 1.1 × 10 15 M . The Sernal-Gerbal method detects a main structure and a much smaller substructure, which are not separated in projection. Conclusions. From its dynamical properties derived from optical data, the Ophiuchus cluster seems overall to be a relaxed structure, or at most a minor merger, though in X-rays the central region (radius ∼150 kpc) may show evidence for merging effects.

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Section: Introductionmentioning

confidence: 68%

Ophiuchus: An optical view of a very massive cluster of galaxies hidden behind the Milky Way

Durret

Wakamatsu

Nagayama

et al. 2015

A&A

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“…Another interesting feature of these CMDs is the branch of very dim and red sources that appears at magnitudes fainter than K s > 16 and colors J−K s > 1.3 (Z−K s > 2.3). These sources can be associated with background galaxies, as some studies suggest (Lucas et al 2008;Coldwell et al 2014;Baravalle et al 2018), although at the faintest magnitudes this sequence is expected to be heavily contaminated with the tail of Galactic stars with higher photometric errors. We note that this sequence is more noticeable in the K s vs J − K s CMD, while the previously mentioned BHB sequence manifests more clearly in the K s vs Z − K s CMD.…”

Section: Cmds Of the Galactic Bulge Fields In The Vvvmentioning

confidence: 99%

Milky Way demographics with the VVV survey

Alonso-García

Saito

Hempel

et al. 2018

A&A

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Context. The inner regions of the Galaxy are severely affected by extinction, which limits our capability to study the stellar populations present there. The Vista Variables in the Vía Láctea (VVV) ESO Public Survey has observed this zone at near-infrared wavelengths where reddening is highly diminished. Aims. By exploiting the high resolution and wide field-of-view of the VVV images we aim to produce a deep, homogeneous, and highly complete database of sources that cover the innermost regions of our Galaxy. Methods. To better deal with the high crowding in the surveyed areas, we have used point spread function (PSF)-fitting techniques to obtain a new photometry of the VVV images, in the ZY JHKs near-infrared filters available. Results. Our final catalogs contain close to one billion sources, with precise photometry in up to five near-infrared filters, and they are already being used to provide an unprecedented view of the inner Galactic stellar populations. We make these catalogs publicly available to the community. Our catalogs allow us to build the VVV giga-CMD, a series of color-magnitude diagrams of the inner regions of the Milky Way presented as supplementary videos. We provide a qualitative analysis of some representative CMDs of the inner regions of the Galaxy, and briefly mention some of the studies we have developed with this new dataset so far.

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“…650) by analyzing their size and colors. Later, Coldwell et al (2014) obtained the photometric properties for the galaxy cluster Suzaku J1759-3450 at z=0.13 in the b261 tile (l=356°. 597, b=−5°.321).…”

Section: Introductionmentioning

confidence: 99%

Searching for Extragalactic Sources in the VISTA Variables in the Vía Láctea Survey

Baravalle

Alonso

Castellón

et al. 2018

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We search for extragalactic sources in the VISTA Variables in the Vía Láctea survey that are hidden by the Galaxy. Herein, we describe our photometric procedure to find and characterize extragalactic objects using a combination of SExtractor and PSFEx. It was applied in two tiles of the survey: d010 and d115, without previous extragalactic IR detections, in order to obtain photometric parameters of the detected sources. The adopted criteria to define extragalactic candidates include CLASS STAR < _ 0 . 3 ; 1.0 < < R 5.0 arcsec; 1 2 2.1 <C <5; and F > 0.002 and the colors: 0.5 <(J-K s ) <2.0 mag; 0.0 <(J-H) <1.0 mag; 0.0 <(H-K s ) <2.0 mag and (J-H) + 0.9 (H-K s ) > 0.44 mag. We detected 345 and 185 extragalactic candidates in the d010 and d115 tiles, respectively. All of them were visually inspected and confirmed to be galaxies. In general, they are small and more circular objects, due to the near-IR sensitivity to select more compact objects with higher surface brightness. The procedure will be used to identify extragalactic objects in other tiles of the VVV disk, which will allow us to study the distribution of galaxies and filaments hidden by the Milky Way.

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Confirmation of a galaxy cluster hidden behind the Galactic bulge using the VVV survey

Cited by 20 publications

References 48 publications

Ophiuchus: An optical view of a very massive cluster of galaxies hidden behind the Milky Way

Ophiuchus: An optical view of a very massive cluster of galaxies hidden behind the Milky Way

Milky Way demographics with the VVV survey

Searching for Extragalactic Sources in the VISTA Variables in the Vía Láctea Survey

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