J/A+A/702/A136 Malin 2 gri images (Junais+, 2025)
Deep imaging of the galaxy Malin 2 shows new faint structures and a candidate
satellite dwarf galaxy.
Junais, Ruiz Cejudo I., Guerra Arencibia S., Trujillo I., Alarcon M.R.,
Serra-Ricart M., Knapen J.H., Duc P.-A.
<Astron. Astrophys. 702, A136 (2025)>
=2025A&A...702A.136J 2025A&A...702A.136J (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Photometry, ugriz
Keywords: galaxies: individual: Malin 2 - galaxies: star formation -
galaxies: structure
Abstract:
Giant Low Surface Brightness (GLSB) galaxies are extreme disk systems
with exceptionally large sizes and low stellar densities. Their
formation and evolution remain poorly constrained due to the
challenges of detecting their faint disks. We present deep, multi-band
optical imaging of Malin 2, a prototypical GLSB galaxy, with the newly
commissioned Two-meter Twin Telescope (TTT) at the Teide Observatory.
Our g, r, and i-band data reach surface brightness depths of 30.3,
29.5, and 28.2mag/arcsec2, tracing the stellar disk of Malin 2 to
nearly 110kpc. We detect new diffuse structures, including a
prominent emission in the northwest coincident with the HI
distribution, and a faint spiral arm-like feature in the southeast. We
also identify a very faint dwarf galaxy, TTT-d1 (g-band central
surface brightness of nearly 26mag/arcsec2), about 130kpc southeast
of Malin 2, possibly its first known satellite ultra-diffuse galaxy. A
multi-directional wedge photometric analysis of Malin 2 shows strong
azimuthal variations in its stellar disk. Compared with nearby spirals
and other GLSBs, Malin 2 lies at the extreme end in radial extent and
stellar mass surface density. The overlap between the asymmetric
stellar emission and a lopsided HI distribution suggests contributions
from tidal interactions in the formation of the giant disk of Malin 2.
Our results highlight the importance of ultra-deep, wide-field imaging
in understanding the structural complexity of giant LSB galaxies.
Upcoming surveys such as LSST will be crucial to determine whether the
features we observe in Malin 2 are common to other giant LSB disk
galaxies.
Description:
g, r and i-band images of Malin 2 from the TTT Telescope (Figure 1 of
the paper).
The zeropoint of all fits the images is 22.5 in the AB magnitude system.
Objects:
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RA (2000) DE Designation(s)
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10 39 52.48 +20 50 49.37 Malin 2 = LSB F568-6
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 114 3 List of fits images
fits/* . 3 Individual fits images
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Name Name
9- 17 F9.5 deg RAdeg Right Ascension of center (J2000)
18- 26 F9.5 deg DEdeg Declination of center (J2000)
28- 32 F5.3 arcsec/pix scale Scale of the image
34- 37 I4 --- Nx Number of pixels along X-axis
39- 42 I4 --- Ny Number of pixels along Y-axis
44- 66 A23 "datime" Obs.date Observation date
68- 72 I5 Kibyte size Size of FITS file
74- 90 A17 --- FileName Name of FITS file, in subdirectory fits
92-114 A23 --- Title Title of the FITS file
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Acknowledgements:
Junais, junais(at)iac.es
(End) Patricia Vannier [CDS] 09-Sep-2025