Unveiling a new structure behind the Milky Way

Abstract

Context. The ZOA does not allow clear optical observations of extragalactic sources behind the Milky Way due to the meaningful extinction of the optical emission of these objects. The observations in NIR wavelengths represent a potential source of astronomical discoveries supporting the detection of new galaxies, completing the picture of the large scale structure in this still little explored area of the sky. Aims. Our aim is to decipher the nature of the overdensity located behind the Milky Way, in the tile b204 of the VVV survey. Methods. We studied an area of six arcmin around a galaxy concentration located at l = 354.82° and b = -9.81°. We selected five galaxies taking into account the source distribution on the sky, in order to optimise the requested time for the observations, and we obtained the spectra with Flamingos 2 long-slit spectrograph at Gemini South 8.1-meter telescope. To identify and characterise the absorption features we have fitted the galaxies underlying spectrum using the starlight code together with the IRTF stellar library. In addition, the spectroscopic findings are reinforced using complementary photometric techniques such as red-sequence and photometric redshift estimation. Results. The mean spectroscopic redshift estimated from the NIR spectra is z = 0.225 +- 0.014. This value presents a good agreement with that obtained from photometric analysis, photoz = 0.21 +- 0.08, and the probability distribution function of the galaxies in the studied region. Also, the red-sequence slope is consistent with the one expected for NIR observations of galaxy clusters. Conclusions. The redshifts obtained from both, photometric and spectroscopic techniques are in good agreement allowing the confirmation of the nature of this structure at z = 0.225 +- 0.014, unveiling a new galaxy cluster, VVVGCl-B J181435-381432, behind the Milky Way bulge.

arXiv comment8 pages, 6 figures

References in corpus (45)

• Astropy: A Community Python Package for Astronomy
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• The broken hierarchy of galaxy formation
• EAZY: A Fast, Public Photometric Redshift Code
• VISTA Variables in the Via Lactea (VVV): The public ESO near-IR variability survey of the Milky Way
• 2MASS Extended Source Catalog: Overview and Algorithms
• The Infrared Telescope Facility (IRTF) Spectral Library: Cool Stars
• The 2MASS Redshift Survey - Description and Data Release
• An Infrared Spectroscopic Sequence of M, L and T Dwarfs
• A New Method For Galaxy Cluster Detection I: The Algorithm
• The 1000 Brightest HIPASS Galaxies: HI Properties
• VVV DR1: The First Data Release of the Milky Way Bulge and Southern Plane from the Near-Infrared ESO Public Survey VISTA Variables in the Via Lactea
• The star formation history of Seyfert 2 nuclei
• The history of star-forming galaxies in the Sloan Digital Sky Survey
• 2MASS Photometric Redshift catalog: a comprehensive three-dimensional census of the whole sky
• Galaxy Groups in the SDSS-DR3
• The Color-Magnitude Effect in Early-Type Cluster Galaxies
• Probing the near infrared stellar population of Seyfert galaxies
• The Universe behind the Milky Way
• Discovery of VVV CL001. A Low-Mass Globular Cluster Next to UKS~1 in the Direction of the Galactic Bulge
• The evolution of the red sequence slope in massive galaxy clusters
• The Parkes HI Zone of Avoidance Survey
• Discovery of a supercluster in the ZOA in Vela
• Galaxy groups in the 2dF redshift survey: Galaxy Spectral Type Segregation in Groups
• The Stellar Spectral Features of Nearby Galaxies in the Near-Infrared: Tracers of Thermally-Pulsing Asymptotic Giant Branch Stars?
• Extragalactic Large-Scale Structures behind the Southern Milky Way. IV. Redshifts Obtained with MEFOS
• The 2MASS Redshift Survey in the Zone of Avoidance
• Optical/NIR stellar absorption and emission-line indices from luminous infrared galaxies
• One more neighbor: The first brown dwarf in the VVV survey
• Rebutting fake news on full spectral fitting
• Near-infrared integrated spectra of Galactic globular clusters: testing simple stellar population models
• Gemini NIFS survey of feeding and feedback processes in nearby Active Galaxies: VI -- Stellar Populations
• Searching for Extragalactic Sources in the VISTA Variables in the Vía Láctea Survey
• Discovery of New Companions to High Proper Motion Stars from the VVV Survey
• The Norma cluster (ACO3627): II. The near infrared K_s-band luminosity function
• Galaxies behind the Galactic plane: First results and perspectives from the VVV Survey
• The VVV Near-IR Galaxy Catalogue beyond the Galactic disk
• A New Cluster of Galaxies towards the Galactic Bulge, Suzaku J1759-3450
• EZOA -- A catalogue of EBHIS HI detected galaxies in the northern Zone of Avoidance
• Confirmation of a cluster of galaxies hidden behind the Galactic bulge using the VVV Survey
• The First Galaxy Cluster Discovered by the VISTA Variables in the Vía Láctea Survey
• The FSVS Cluster Catalogue: Galaxy Clusters and Groups in the Faint Sky Variability Survey
• Overdensity of VVV galaxies behind the Galactic bulge
• A deep near-infrared view of the Ophiuchus galaxy cluster
• Mass Calibration of Galaxy Clusters at Redshift 0.1-1.0 using Weak Lensing in the Sloan Digital Sky Survey Stripe 82 Co-add

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