University of Oulu

Cantiello, M., Venhola, A., Grado, A., Paolillo, M., D’Abrusco, R., Raimondo, G., Quintini, M., Hilker, M., Mieske, S., Tortora, C., Spavone, M., Capaccioli, M., Iodice, E., Peletier, R., Barroso, J. F., Limatola, L., Napolitano, N., Schipani, P., van de Ven, G., … Covone, G. (2020). The Fornax Deep Survey with VST. Astronomy & Astrophysics, 639, A136.

The Fornax Deep Survey with VST : IX. Catalog of sources in the FDS area with an example study for globular clusters and background galaxies

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Author: Cantiello, Michele1; Venhola, Aku2; Grado, Aniello3;
Organizations: 1INAF Osservatorio Astr. d’Abruzzo, Via Maggini, 64100 Teramo, Italy
2Astronomy Research Unit, University of Oulu, Pentti Kaiteran katu 1, 90014 Oulu, Finland
3INAF – Osservatorio Astr. di Capodimonte Napoli, Salita Moiariello 80131, Napoli, Italy
4Dip. di Fisica “E. Pancini”, Universitá di Napoli Federico II, C.U. di Monte Sant’Angelo, Via Cintia, 80126 Naples, Italy
5INFN, Sez. di Napoli, Via Cintia, 80126 Napoli, Italy
6Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, 02138 Cambridge, MA, USA
7European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany
8European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago, Chile
9INAF – Osservatorio Astr. di Arcetri, Largo Enrico Fermi 5, 50125 Firenze, Italy
10Kapteyn Astronomical Institute, University of Groningen, PO Box 72, 9700 AV Groningen, The Netherlands
11Instituto de Astrofśica de Canarias, Calle Vía Láctea s/n, 38200 La Laguna, Tenerife, Spain
12Depto. Astrofísica, Universidad de La Laguna, Calle Astrofísico Francisco Sánchez s/n, 38206 La Laguna, Tenerife, Spain
13School of Physics and Astronomy, Sun Yat-sen University, Zhuhai Campus, 2 Daxue Road, Xiangzhou District, Zhuhai, PR China
14Department of Astrophysics, University of Vienna Türkenschanzstraße 17, 1180 Vienna, Austria
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 40.3 MB)
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Language: English
Published: EDP Sciences, 2020
Publish Date: 2020-09-24


Context: A possible pathway for understanding the events and the mechanisms involved in galaxy formation and evolution is an in-depth investigation of the galactic and inter-galactic fossil sub-structures with long dynamical timescales: stars in the field and in stellar clusters.

Aims: This paper continues the Fornax Deep Survey (FDS) series. Following previous studies dedicated to extended Fornax cluster members, we present the catalogs of compact stellar systems in the Fornax cluster, as well as extended background sources and point-like sources.

Methods: We derived ugri photometry of ∼1.7 million sources over the ∼21 square degree area of FDS centered on the bright central galaxy NGC 1399. For a wider area, of ∼27 square degrees extending in the direction of NGC 1316, we provided gri photometry for ∼3.1 million sources. To improve the morphological characterization of sources, we generated multi-band image stacks by coadding the best-seeing gri-band single exposures with a cut at full width at half maximum (FWHM) ≤ 0.″9. We used the multi-band stacks as master detection frames, with a FWHM improved by ∼15% and a FWHM variability from field to field reduced by a factor of ∼2.5 compared to the pass-band with the best FWHM, namely the r-band. The identification of compact sources, in particular, globular clusters (GC), was obtained from a combination of photometric (e.g., colors, magnitudes) and morphometric (e.g., concentration index, elongation, effective radius) selection criteria, also taking as reference the properties of sources with well-defined classifications from spectroscopic or high-resolution imaging data.

Results: Using the FDS catalogs, we present a preliminary analysis of GC distributions in the Fornax area. The study confirms and extends further previous results that were limited to a smaller survey area. We observed the inter-galactic population of GCs, a population of mainly blue GCs centered on NGC 1399, extending over ∼0.9 Mpc, with an ellipticity ϵ ∼ 0.65 and a small tilt in the direction of NGC 1336. Several sub-structures extend over ∼0.5 Mpc along various directions. Two of these structures do not cross any bright galaxy; one of them appears to be connected to NGC 1404, a bright galaxy close to the cluster core and particularly poor in GCs. Using the gri catalogs, we analyze the GC distribution over the extended FDS area and do not find any obvious GC sub-structure bridging the two brightest cluster galaxies, namely, NGC 1316 and NGC 1399. Although NGC 1316 is more than twice as bright of NGC 1399 in optical bands, using gri data, we estimate a GC population that is richer by a factor of ∼3−4 around NGC 1399, as compared to NGC 1316, out to galactocentric distances of ∼40’ or ∼230 kpc.

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Series: Astronomy and astrophysics
ISSN: 0004-6361
ISSN-E: 1432-0746
ISSN-L: 0004-6361
Volume: 639
Article number: A136
DOI: 10.1051/0004-6361/202038137
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: This research was made possible through the use of the AAVSO Photometric All-Sky Survey (APASS), funded by the Robert Martin Ayers Sciences Fund and NSF AST-1412587. This work is based on visitor mode observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under the following VST GTO programs: 094.B-0512(B), 094.B-0496(A), 096.B-0501(B), 096.B-0582(A). INAF authors acknowledge financial support for the VST project (P. I. P. Schipani). We acknowledge the use of data from the SKyMapper survey. The national facility capability for SkyMapper has been funded through ARC LIEF grant LE130100104 from the Australian Research Council, awarded to the University of Sydney, the Australian National University, Swinburne University of Technology, the University of Queensland, the University of Western Australia, the University of Melbourne, Curtin University of Technology, Monash University and the Australian Astronomical Observatory. SkyMapper is owned and operated by The Australian National University’s Research School of Astronomy and Astrophysics. The survey data were processed and provided by the SkyMapper Team at ANU. The SkyMapper node of the All-Sky Virtual Observatory (ASVO) is hosted at the National Computational Infrastructure (NCI). Development and support the SkyMapper node of the ASVO has been funded in part by Astronomy Australia Limited (AAL) and the Australian Government through the Common-wealth’s Education Investment Fund (EIF) and National Collaborative Research Infrastructure Strategy (NCRIS), particularly the National eResearch Collaboration Tools and Resources (NeCTAR) and the Australian National Data Service Projects (ANDS). MP acknowledges financial contribution from the agreement ASI-INAF n.2017-14-H.O. JFB acknowledges support through the RAVET project by the grant AYA2016-77237-C3-1-P from the Spanish Ministry of Science, Innovation and Universities (MCIU) and through the IAC project TRACES which is partially supported through the state budget and the regional budget of the Consejería de Economía, Industria, Comercio y Conocimiento of the Canary Islands Autonomous Community. GvdV acknowledges funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme under grant agreement No 724857 (Consolidator Grant ArcheoDyn). CT acknowledges funding from the INAF PRIN-SKA2017 program
Copyright information: © ESO 2020.