J/A+A/698/A214 VVV galaxies behind the Milky Way (Galdeano+, 2025)
Enlightening the Universe behind the Milky Way bulge.
II. Morphological classification and galaxy properties.
Galdeano D., Coldwell G., Alonso S., Duplancic F., Lucas P.W., Fernandez J.,
Perez N., Pereyra L., Mesa V., Minniti D., Smith L.C., Zarate F.M.
<Astron. Astrophys. 698, A214 (2025)>
=2025A&A...698A.214G 2025A&A...698A.214G (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, IR ; Photometry, infrared ; Morphology
Keywords: catalogs - surveys - galaxies: general - galaxies: statistics -
infrared: galaxies
Abstract:
The detection of extragalactic sources beyond the Milky Way is limited
by the location of solar system. In the Zone of Avoidance (ZOA),
optical observations are hindered by stellar crowding and Galactic
absorption. To fully understand the background galaxy population in
this region, observations at longer wavelengths are needed.
The objective of this study is to determine the characteristics of
galaxies situated behind the Milky Way bulge through the use of
near-infrared (NIR) data obtained from the VISTA Variables in Via
Lactea (VVV) survey.
The galaxy candidates were visually confirmed, and a morphological
classification of all sources was performed based on their appearance,
differentiating between elliptical, spiral, undefined, and doubtful
galaxies. Additionally, the surrounding area was classified based on
the number of sources detected in the same target field. Isolated
galaxies, galaxies with close companions, and galaxies in denser
environments were catalogued.
Following a visual inspection, 14480 galaxy candidates were classified
morphologically: 3702 as elliptical, 1704 as spiral, 6425 as
undefined, and 2649 as doubtful. Environmental classification showed
that 73.9% were isolated, 12.4% had close companions, and 13.7% were
in denser environments. Our catalogue shows slower proper motions than
star catalogues. The majority of galaxies classified as elliptical and
spiral manifest SExtractor parameters that are indicative of this
category of sources. Additionally, elliptical galaxies in denser
environments appear redder than spiral galaxies in isolated
environments.
A total of 14480 galaxy candidates were subjected to a morphological
classification in the Milky Way bulge region. This result verifies the
efficacy of the VVV/VVVX survey in identifying and characterising a
diverse range of galaxies and extragalactic structures that are
obscured by the Milky Way, thereby contributing to a more profound
understanding of the universe in the ZOA.
Description:
14480 galaxy candidates were detected in the VVV survey in the Milky
way region, 14224 of which were catalogued in D24 for the first time.
The galaxy candidates were subjected to a visual inspection to
determine their morphology. This process was crucial because the
results we obtained provide fundamental information for the
characterisation and morphological classification of the galaxies.
This aspect is highly relevant in the context of the study of the ZOA.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 173 14480 Catalogue of VVV galaxies behind the Milky Way
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See also:
II/348 : VISTA Variable in the Via Lactea Survey DR2 (Minniti+, 2017)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 22 A22 --- Name Unique identifier (VVVJHHMMSS.ss+DDMMSS.s)
24- 25 I2 h RAh Right ascension (J2000.0)
27- 28 I2 min RAm Right ascension (J2000.0)
30- 34 F5.2 s RAs Right ascension (J2000.0)
36 A1 --- DE- Ceclination sign (J2000.0)
37- 38 I2 deg DEd Ceclination (J2000.0)
40- 41 I2 arcmin DEm Ceclination (J2000.0)
43- 47 F5.2 arcsec DEs Ceclination (J2000.0)
48- 52 F5.2 mag Zmag3 Aperture magnitude within 3 pixels in Z
54- 57 F4.2 mag e_Zmag3 Error on Aperture magnitude
within 3 pixels in Z
59- 63 F5.2 mag Zmag Total magnitude in Z
65- 68 F4.2 mag e_Zmag Error on Total magnitude Z
70- 74 F5.2 mag Ymag3 Aperture magnitude within 3 pixels in Y
76- 79 F4.2 mag e_Ymag3 Error on Aperture magnitude
within 3 pixels in Y
81- 85 F5.2 mag Ymag Total magnitude in Y
87- 90 F4.2 mag e_Ymag Error on Total magnitude Y
92- 96 F5.2 mag Jmag3 Aperture magnitude within 3 pixels in J
98-101 F4.2 mag e_Jmag3 Error on Aperture magnitude
within 3 pixels in J
103-107 F5.2 mag Jmag Total magnitude in J
109-113 F5.2 mag e_Jmag Error on Total magnitude J
115-119 F5.2 mag Hmag3 Aperture magnitude within 3 pixels in H
121-124 F4.2 mag e_Hmag3 Error on Aperture magnitude
within 3 pixels in H
126-130 F5.2 mag Hmag Total magnitude in H
132-135 F4.2 mag e_Hmag Error on Total magnitude H
137-141 F5.2 mag Ksmag3 Aperture magnitude within 3 pixels in Ks
143-146 F4.2 mag e_Ksmag3 Error on Aperture magnitude
within 3 pixels in Ks
148-152 F5.2 mag Ksmag Total magnitude in Ks
154-157 F4.2 mag e_Ksmag Error on Total magnitude Ks
159-163 F5.2 arcsec rhalf Half light radius
165-168 F4.2 --- CS [0/0.5] Class Star (0: galaxy, 1: star)
170-171 I2 --- MType [1/88] Morphological type (1)
173 A1 --- Env [0124] Environment (2)
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Note (1): Morphological type as follows:
1 = ellipticals
5 = spirals
10 = undefined galaxies
88 = doubtful galaxies
Note (2): Environment code as follows:
0 = isolated galaxies
1 = 2 cases, VVVJ175819.71-405105.3 and VVVJ182936.64-282600.5,
not explained
2 = galaxies with a close companion
4 = galaxies in denser environments, that is three or more
galaxies are observed
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Acknowledgements:
Daniela Galdeano, dgaldeano(at)unsj-cuim.edu.ar
(End) Daniela Galdeano [UNSJ], Patricia Vannier [CDS] 28-May-2025