J/other/OJAP/7.93 NGC 3640 and NGC 3641 globular cluster system (Ennis+, 2024)
Imprints of interaction processes in the globular cluster system of NGC 3640.
Ennis, A.I., Caso J.P., Bassino L.P.
<Open Journal of Astrophysics, 7, 93 (2024)>
=2024OJAp....7E..93E 2024OJAp....7E..93E (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Clusters, globular ; Photometry, ugriz
Keywords: early-type galaxies - galaxies - globular star clusters
Abstract:
We present a wide-field study of the globular cluster systems (GCS) of
the elliptical galaxy NGC 3640 and its companion NGC 3641, based on
observations from Gemini Multi-Object Spectrograph/Gemini using gri
filters. NGC 3640 is a shell galaxy which presents a complex
morphology, which previous studies have indicated as the sign of a
recent 'dry' merger, although whether its nearest neighbour could have
influenced these substructures remains an open question. In this work,
we trace the spatial distribution of the globular clusters (GCs) as
well as their colour distribution, finding a potential bridge of red
(metal-rich) GCs that connects NGC 3640 to its less massive companion,
and signs that the blue (metal-poor) GCs were spatially disturbed by
the event that created the shells. While NGC 3640 presents a typical
bimodal colour distribution, the GCS attributed to NGC 3641 appears
unimodal, with most GCs presenting an intermediate colour in
comparison to those closer to its companion.
Description:
We perform a wide-field photometric study of the GCS of NGC 3640 and
NGC 3641, using data obtained from GMOS/Gemini. We attribute GCs to
the GCS of each galaxy based on projected distance, and analyze each
of them separately.
These are the catalogues of globular cluster candidates associated to
NGC 3640 and NGC 3641, with their PSF magnitudes.
Objects:
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RA (2000) DE Designation(s)
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11 21 06.85 +03 14 05.1 NGC 3640 = UGC 6368
11 21 08.81 +03 11 40.5 NGC 3641 = UGC 6370
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
gcs3640.dat 484 483 Catalog of GC candidates associated to NGC 3640
gcs3641.dat 484 162 Catalog of GC candidates associated to NGC 3641
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Byte-by-byte Description of file: gcs3640.dat gcs3641.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Index Index
5- 24 F20.15 pix Xcenter Position in X axis
26- 43 F18.13 pix Ycenter Position in Y axis
45- 62 F18.15 mag gmagi Instrumental g magnitude
64- 81 F18.15 mag rmagi Instrumental r magnitude
83-100 F18.15 mag imagi Instrumental i magnitude
102-122 F21.18 --- gsha Sharpness of PSF fit in g magnitude
124-144 F21.18 --- rsha Sharpness of PSF fit in r magnitude
146-166 F21.18 --- isha Sharpness of PSF fit in i magnitude
168-186 F19.17 --- gchi2 Chi squared from PSF fit in g magnitude
188-206 F19.17 --- rchi2 Chi squared from PSF fit in r magnitude
208-226 F19.17 --- ichi2 Chi squared from PSF fit in i magnitude
228-247 F20.18 mag e_gmag Error in g magnitude
249-268 F20.18 mag e_rmag Error in r magnitude
270-289 F20.18 mag e_imag Error in i magnitude
291-308 F18.15 mag gmag Standard g magnitude
310-327 F18.15 mag rmag Standard r magnitude
329-346 F18.15 mag imag Standard i magnitude
348-366 F19.14 pix Rad3640 Distance to NGC 3640
368-386 F19.14 pix Rad3641 Distance to NGC 3641
388-405 F18.16 mag g-i g-i colour index
407-425 F19.17 mag g-r g-r colour index
427-446 F20.18 mag r-i r-i colour index
448-465 F18.14 deg RAdeg Right Ascension (J2000)
467-484 F18.16 deg DEdeg Declination (J2000)
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Acknowledgements:
Ana Ennis, ennis.ana(at)gmail.com
(End) Patricia Vannier [CDS] 12-Sep-2025