J/MNRAS/516/2300 352 ultraviolet sources from NSR of Centaurus A (Joseph+, 2022)
UVIT view of Centaurus A a detailed study on positive AGN feedback.
Joseph P., Sreekumar P., Stalin C.S., Paul K.T., Mondal C., George K.,
Mathew B.
<Mon. Not. R. Astron. Soc. 516, 2300-2313 (2022)>
=2022MNRAS.516.2300J 2022MNRAS.516.2300J (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; YSOs ; Populations, stellar ; Positional data ;
Photometry, ultraviolet ; Stars, ages
Keywords: galaxies: jets - galaxies: star formation - ultraviolet: galaxies
Abstract:
Supermassive black holes at the centre of active galactic nuclei
(AGNs) produce relativistic jets that can affect the star formation
characteristics of the AGN hosts. Observations in the ultraviolet (UV)
band can provide an excellent view of the effect of AGN jets on star
formation. Here, we present a census of star formation properties in
the Northern Star-forming Region (NSR) that spans about 20 kpc of the
large radio source Centaurus A hosted by the giant elliptical galaxy
NGC 5128. In this region, we identified 352 UV sources associated with
Cen A using new observations at an angular resolution of <1.5 arcsec
observed with the Ultra-Violet Imaging Telescope (UVIT) onboard
AstroSat. These observations were carried out in one far-ultraviolet
(FUV; λmean = 1481 Å) and three near-ultraviolet (NUV; with
λmean of 2196, 2447, and 2792 Å, respectively) bands. The
star-forming sources identified in UV tend to lie in the direction of
the jet of Cen A, thereby suggesting jet triggering of star formation.
Separating the NSR into Outer and Inner regions, we found the stars in
the Inner region to have a relatively younger age than the Outer
region, suggesting that the two regions may have different star
formation histories. We also provide the UVIT source catalogue in the
NSR.
Description:
We performed UV observations of the NSR using Ultra-Violet Imaging
Telescope (UVIT) in different UV filters with an angular resolution
better than 1.5 arcsec. This work presents the results from our new
observations in the one FUV and three NUV bands. We proceed to data
reduction with UVIT pipeline. As explained in section 2 and 2.2
detection of objects, centroid estimation and isophotal photometry
were carried out for all the 417 detected sources in each filter on
which we excluded foreground and background sources (using Gaia proper
motions). Also, we assume that the diffuse UV emission comes from hot
gas and point-like emission from Young stellar populations in the NSR.
We categorized point-like sources as sites of star formation and the
remaining as diffuse emission sources. (i.e section 2 for more
details). As shown in figure 3 of section 2, we denoted 83
star-forming and 269 diffuse sources, fluxes results are presented in
table2.dat.
Next in section 3.3 SSP, in order to estimate ages, we simulated
high-resolution UV spectra spanning ages up to 1 Gyr to compare them
to observations from three UV colours. The mean of the two age
estimates from N219M-F148W and N245M-F148W colours was taken as the
final age value for each source. The colours and estimated ages for
the Inner and Outer regions are given in tableb1.dat and tableb2.dat,
respectively.
More, since we do not have redshift information for the final NSR
catalogue of 352 sources to conclusively ascertain their membership in
the NSR of Cen A, our list of sources should be considered as
candidates (while contamination has been controlled, there can still
be intruders in this list). See sections 3.1 and 3.2 for connection
between sources and jets.
Objects:
----------------------------------------------------------------------------
RA (2000) DE Designation(s)
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13 25 27.61 -43 01 08.8 Centaurus A = 0FGL J1325.4-4303
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File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 161 352 NSR source catalogue and their properties from
observations with UVIT telescope
tableb1.dat 236 16 Observing properties and estimated ages of
star-forming sources inside NSR Inner region
tableb2.dat 236 61 Observing properties and estimated ages of
star-forming sources inside NSR Outer region
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See also:
J/MNRAS/474/4056 : Cen A MWA 154MHz image (McKinley+, 2018)
J/MNRAS/478/3447 : SDSS post-merger galaxies HI data (Ellison+, 2018)
J/A+A/595/A65 : APEX spectra of Centaurus A (Salome+, 2016)
J/A+A/608/A98 : APEX spectra of Centaurus A (Salome+, 2017)
J/other/NatAs/6.109 : Centaurus A (NGC 5128) 185MHz MWA image (McKinley+, 2022)
I/352 : Distances to 1.47 billion stars in Gaia EDR3
(Bailer-Jones+, 2021)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- ID Identifier raw number (label)
5- 20 F16.12 deg RAdeg Right ascension (J2000) (RA_J2000)
22- 38 F17.13 deg DEdeg Declination (J2000) (DEC_J2000)
40- 57 F18.15 pc2 Area The isophotal areas of NSR sources for
photometry acquisition (Area)
59- 70 E12.6 10-2W/m2/nm FF148W The UVIT flux in FUV F148W filter
centered on 148.1nm (F148W flux)
72- 83 E12.6 10-2W/m2/nm e_FF148W Uncertainty of FF148W (F148W flux error)
85- 96 E12.6 10-2W/m2/nm FN219M The UVIT flux in NUV N219M filter
centered on 219.6nm (N219M flux)
98-109 E12.6 10-2W/m2/nm e_FN219M Uncertainty of FN219M (N219M flux error)
111-122 E12.6 10-2W/m2/nm FN245M The UVIT flux in NUV N245M filter
centered on 244.7nm (N245M flux)
124-135 E12.6 10-2W/m2/nm e_FN245M Uncertainty of FN245M (N245M flux error)
137-148 E12.6 10-2W/m2/nm FN279N The UVIT flux in NUV N279N filter
centered on 279.2nm (N279N flux)
150-161 E12.6 10-2W/m2/nm e_FN279N Uncertainty of FN279N (N279N flux error)
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Byte-by-byte Description of file: tableb1.dat tableb2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- ID Identifier raw number (label)
5- 20 F16.12 deg RAdeg Right ascension (J2000) (RA_J2000)
22- 38 F17.13 deg DEdeg Declination (J2000) (DEC_J2000)
40- 56 F17.14 pc2 Area The isophotal areas of NSR sources for
photometry acquisition (Area)
58- 69 E12.6 10-2W/m2/nm FF148W The UVIT flux in FUV F148W filter
centered on 148.1nm (F148W_flux)
71- 82 E12.6 10-2W/m2/nm e_FF148W Uncertainty of FF148W (F148Wfluxerror)
84- 95 E12.6 10-2W/m2/nm FN219M The UVIT flux in NUV N219M filter
centered on 219.6nm (N219M_flux)
97-108 E12.6 10-2W/m2/nm e_FN219M Uncertainty of FN219M (N219Mfluxerror)
110-121 E12.6 10-2W/m2/nm FN245M The UVIT flux in NUV N245M filter
centered on 244.7nm (N245M_flux)
123-134 E12.6 10-2W/m2/nm e_FN245M Uncertainty of FN245M (N245Mfluxerror)
136-147 E12.6 10-2W/m2/nm FN279N The UVIT flux in NUV N279N filter
centered on 279.2nm (N279N_flux)
149-160 E12.6 10-2W/m2/nm e_FN279N Uncertainty of FN279N (N279Nfluxerror)
162-179 F18.15 mag C1mag Observed N219M-F148W colour corrected from
dust attenuation (N219M-F148W)
181-198 F18.15 mag C2mag Observed N245M-F148W colour corrected from
dust attenuation (N245M-F148W)
200-217 F18.15 mag C3mag Observed N245M-N219M colour corrected from
dust attenuation (N245M-N219M)
219-236 F18.14 Myr Age ? Estimated ages from starburst99
simulated high-resolution UV spectra
spanning ages up to 1 Gyr (Age)
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History:
From electronic version of the journal
(End) Luc Trabelsi [CDS] 23-Jul-2025