J/AJ/169/188 Photometric properties of UV sources near IC 4329A (Ganguly+, 2025)
AstroSat/UVIT Far- and Near-UV deep field around IC 4329A.
Ganguly P., Rani P., Dewangan G.C.
<Astron. J., 169, 188 (2025)>
=2025AJ....169..188G 2025AJ....169..188G
ADC_Keywords: Photometry, ultraviolet; X-ray sources; Optical; Galaxies;
Redshifts
Keywords: Ultraviolet photometry ; Catalogs ; Active galaxies ; X-ray sources
Abstract:
We present high-resolution near-ultraviolet (NUV) and far-ultraviolet
(FUV) deep imaging of the field around the Seyfert galaxy IC 4329A
based on five observations performed with the Ultra-Violet Imaging
Telescope (UVIT) onboard AstroSat. The long exposures of 82.9ks in the
NUV (N245M; λmean=2447Å; Δλ=270Å) and 92.2ks
in the FUV (F154W;λmean=1541Å; Δλ=380Å)
bands constitute the deepest observations with 5σ detection
limits of AB magnitudes mNUV=26.2 and mFUV=25.7. Leveraging UVIT's
excellent angular resolution (FWHM∼1.2"-1.8", we performed a detailed
analysis of the IC 4329A field and detected (above the 5σ
significance level) a total of 4437 and 456 sources in the NUV and FUV
bands, respectively. A large number of these detected sources were
previously unknown. We performed astrometry and photometry on all
detected sources. By cross-matching our catalog with the Gaia-DR3 and
XMM-Newton DR12 catalogs, we found 651 optical and 97 X-ray
counterparts of our sources. Additionally, we explored the UV
variability of point sources, identifying 28 NUV sources as variable
with a significance above the 2.5σ level. Of these, only three
sources exhibited variability in the FUV band. Utilizing the NUV and
Gaia fluxes, we determined that two previously cataloged white dwarf
candidates are misclassified. Furthermore, we highlight galaxies with
atypical morphology, including ring-like structures, multiple compact
central sources, bifurcating spiral arms, and so on. Follow- up
optical spectroscopy and multiwavelength observations are imperative
to further investigate the nature of the sources within this field.
Description:
The UltraViolet Imaging Telescope (UVIT), on board AstroSat, houses
two telescopes, each with a primary mirror of 375mm in diameter and a
field of view (FOV) of a circular region with 28' diameter. The two
telescopes constitute three channels: far-UV (FUV; 130-180nm),
near-UV (NUV; 200-300nm), and visible (VIS; 350-550nm).
AstroSat/UVIT observed the IC 4329A field five times during February
to June 2017. The UVIT was operated in the photon-counting mode using
two broadband filters: FUV/F154W (λmean=1541Å,
Δλ=380Å) and NUV/N245M (λmean=2447Å,
Δλ=280Å). We obtained the level1 data for the five
observations from the AstroSat data archive. The net exposure time of
the merged image in NUV is 82.9ks, and in the FUV band it is 92.2ks.
Our final source catalog contains the position and photometric
properties of 4437 NUV sources detected above an SNR of 5, with 1871
point sources and 2566 extended sources. Out of these 4437 NUV
sources, only 456 sources are detected in the FUV band, 651 sources
have Gaia/optical, and 97 sources have XMM-Newton X-ray counterparts.
We found only 10 sources with counterparts in all the three bands,
that is, FUV, optical, and X-ray.
Objects:
-------------------------------------------------------
RA (2000) DE Designation(s)
-------------------------------------------------------
13 49 19.26 -30 18 34.2 IC 4329A = 1ES 1346-30.0
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table9.dat 377 4437 Final catalogue
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See also:
B/simbad : Simbad objects catalogue (M.Wenger 2000)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
IX/68 : XMM-Newton Serendipitous Source Catalogue 4XMM-DR12 (Webb+, 2023)
IX/69 : XMM-Newton Serendipitous Source Catalogue 4XMM-DR13 (Webb+, 2023)
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
VII/294 : The Million Quasars (Milliquas) catalogue, version 8 (Flesch, 2023)
J/AJ/132/1729 : Hubble Ultra Deep Field BVI-dropout sources (Beckwith+, 2006)
J/ApJS/207/19 : Hard X-ray survey from Swift-BAT 2004-2010 (Baumgartner+, 2013)
J/ApJ/766/60 : GALEX Time Domain Survey I. UV variable sources (Gezari+, 2013)
J/A+A/638/A27 : Redshift database towards Shapley Superclust. (Quintana+, 2020)
J/MNRAS/508/3877 : Catalogue of white dwarfs in Gaia EDR3 (Gentile+, 2021)
J/ApJ/914/54 : Deep FUV obs. of NGC6946, NGC628 & NGC5457 (Yadav+, 2021)
J/ApJS/264/40 : The AstroSat UV GOODS-N Deep Field cat. (AUDFn) (Mondal+, 2023)
J/ApJS/275/28 : The AstroSat UV Deep Field south. I. GOODS-S (Saha+, 2024)
J/A+A/687/A313 : 1UVA catalog of time variable UV sources (Buehler+, 2024)
J/ApJS/275/34 : UVIT DR1, comprehensive catalog of UVIT obs. (Piridi+, 2024)
http://astrobrowse.issdc.gov.in/astro_archive/archive/Home.jsp : AstroSat data
archive
Byte-by-byte Description of file: table9.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- ID [1/4437] Source identification number in
the catalogue
6- 15 F10.6 deg RAdeg-NUV Right ascension in NUV (J2000)
17- 26 F10.6 deg DEdeg-NUV Declination in NUV (J2000)
28- 34 F7.4 arcsec a-NUV [0/49.54] Semi-major axis of the
elliptical Kron aperture, NUV (1)
36- 42 F7.4 arcsec b-NUV [0/28.31] Semi-minor axis of the
elliptical Kron aperture, NUV (1)
44- 48 F5.1 deg PA-NUV Position angle of the elliptical Kron
aperture, NUV (1)
50- 58 E9.3 10+7W/m3 Flux-NUV [7.3e-19/1.71e-14] Estimated NUV flux in
erg/s/cm2/A
60- 68 E9.3 10+7W/m3 e_Flux-NUV [1.19e-19/1.23e-17] Uncertainty in
Flux-NUV
70- 75 F6.3 mag NUVmag [15.1/26] Estimated NUV AB magnitude
77- 83 E7.5 mag e_NUVmag [7.7e-4/0.181] Uncertainty in NUVmag
85 I1 --- NUV-flag [0/1] Extraction Flag for NUV source (2)
87 I1 --- Category [0/1] Source category (3)
89- 95 F7.2 --- SNR-NUV [5/1390] Signal-to-noise of source in
NUV
97- 102 F6.4 --- Fvar-NUV [0/0.68] Fractional excess variability
amplitude for the source in the NUV band
104- 110 F7.5 --- e_Fvar-NUV [0/0.22] 1σ error on Fvar-NUV
112- 121 F10.6 deg RAdeg-FUV ? Right ascension in FUV (J2000)
123- 132 F10.6 deg DEdeg-FUV ? Declination in FUV (J2000)
134- 140 F7.4 arcsec a-FUV [0/51.21]? Semi-major axis of the
elliptical Kron aperture, FUV (1)
142- 148 F7.4 arcsec b-FUV [0/28.2]? Semi-minor axis of the
elliptical Kron aperture, FUV (1)
150- 154 F5.1 deg PA-FUV ? Position angle of the elliptical Kron
aperture, FUV (1)
156- 164 E9.3 10+7W/m3 Flux-FUV [4.1e-18/9.35e-15]? Estimated FUV flux
in erg/s/cm2/A
166- 174 E9.3 10+7W/m3 e_Flux-FUV [6.71e-19/2.1e-17]? Uncertainty in
Flux-FUV
176- 181 F6.3 mag FUVmag [16.6/25.2]? Estimated FUV AB magnitude
183- 189 F7.5 mag e_FUVmag [2.4e-3/0.185]? Uncertainty in FUVmag
191- 196 F6.2 --- SNR-FUV [5/427]? Signal-to-noise of source in
FUV
198- 203 F6.4 --- Fvar-FUV [0/0.27]? Fractional excess variability
amplitude for the source in the FUV band
205- 210 F6.4 --- e_Fvar-FUV [0/0.1]? 1σ error on Fvar-FUV
212- 220 F9.5 mag FUV-NUV [-2.4/5.14]? FUV-NUV magnitude
222- 240 I19 --- GaiaDR3 ? Gaia DR3 (I/355) source ID
242- 251 F10.6 deg RAdeg-Gaia ? Right Ascension, Gaia DR3,
(ICRS at Epoch=2016.0)
253- 262 F10.6 deg DEdeg-Gaia ? Declination, Gaia DR3,
(ICRS at Epoch=2016.0)
264- 272 F9.1 ct/s Flux-Gaia [44.7/3.33e+6]? Flux of the source in
Gaia DR3 catalogue in e-/s
274- 281 F8.3 ct/s e_Flux-Gaia [0.8/4900]? Uncertainty in Flux-Gaia in
e-/s
283- 289 F7.4 mag Gmag [9.49/21.7]? AB magnitude of the source
calculated from Flux-Gaia (4)
291 I1 --- Gaia-Class [0/1]? Category of the source according
to Gaia proper motion (3)
293- 300 F8.4 mas/yr pmTot [0/107]? Gaia DR3 total proper motion
302- 316 I15 --- 4XMM ? 4XMM DR12 (IX/68) source index
318- 327 F10.6 deg RAdeg-4XMM ? Right ascension, 4XMM DR12 (J2000)
329- 338 F10.6 deg DEdeg-4XMM ? Declination, 4XMM DR12 (J2000)
340- 347 E8.2 mW/m2 Flux-4XMM [3.4e-15/9.3e-11]? Flux of the source in
4XMM DR12 catalogue in erg/s/cm2
349- 356 E8.2 mW/m2 e_Flux-4XMM [2.7e-15/3.4e-13]? Uncertainty in
Flux-4XMM
358- 369 F12.6 --- z [0.01/1.44]? Redshift
371- 377 E7.2 --- e_z [8.3e-5/3e-4]? Uncertainty in z
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Note (1): Corresponding to Kron factor 2.5. Given only for the
extended sources. For point sources value is quoted as 0.0.
Note (2): Extraction Flag for NUV source as follows:
1 = photometric measurements are affected due to nearby bright sources,
(more than 10% area affected); 687 occurrences
0 = unaffected; 3750 occurrences
Note (3): Source category as follows:
1 = point source (568 occurrences)
0 = extended source (83 occurrences)
Note (4): These magnitudes are calculated from GAIA FLUX (Flux-Gaia)
applying the zero-point magnitude in AB magnitude system.
Available at https://www.cosmos.esa.int/web/gaia/edr3-passbands
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History:
From electronic version of the journal
(End) Prepared by [AAS], Robin Leichtnam [CDS] 12-Jan-2026