J/MNRAS/469/3444 Survey of Centaurus A's Baryonic Structures II. (Taylor+, 2017)
The Survey of Centaurus A's Baryonic Structures (SCABS).
II. The extended globular cluster system of NGC 5128 and its nearby environment.
Taylor M.A., Puzia T.H., Munoz R.P., Mieske S., Lancon A., Zhang H.,
Eigenthaler P., Bovill M.S.
<Mon. Not. R. Astron. Soc., 469, 3444-3467 (2017)>
=2017MNRAS.469.3444T 2017MNRAS.469.3444T (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Photometry, SDSS ; Positional data
Keywords: galaxies: elliptical and lenticular, cD - galaxies: formation -
galaxies: individual: NGC 5128 - galaxies: star clusters: general
Abstract:
New wide-field u'g'r'i'z' Dark Energy Camera observations centred on
the nearby giant elliptical galaxy NGC 5128 covering ∼21 deg2 are
used to compile a new catalogue of ∼3200 globular clusters (GCs). We
report 2404 newly identified candidates, including the vast majority
within ∼140kpc of NGC 5128. We find evidence for a transition at a
galactocentric radius of Rgc~=55kpc from GCs 'intrinsic' to NGC 5128
to those likely to have been accreted from dwarf galaxies or that may
transition to the intragroup medium of the Centaurus A galaxy group.
We fit power-law surface number density profiles of the form
ΣN,Rgc∝Rgc_Γ and find that inside the
transition radius, the red GCs are more centrally concentrated than
the blue, with Γinner,red~=-1.78 and
Γinner,blue~=-1.40, respectively. Outside this region both
profiles flatten, more dramatically for the red GCs
(Γouter,red~=-0.33) compared to the blue
(Γouter,blue~= -0.61), although the former is more likely to
suffer contamination by background sources. The median
(g'-z')0=1.27mag colour of the inner red population is consistent
with arising from the amalgamation of two giant galaxies each less
luminous than present-day NGC 5128. Both inwards and outwards of the
transition radius, we find the fraction of blue GCs to dominate over
the red GCs, indicating a lively history of minor mergers. Assuming
the blue GCs to originate primarily in dwarf galaxies, we model the
population required to explain them, while remaining consistent with
NGC 5128's present-day spheroid luminosity. We find that several dozen
dwarfs of luminosities Ldw,V~= 106-9.3LV,☉, following a
Schechter luminosity function with a faint-end slope of
-1.50≤α≤-1.25 is favoured, many of which may have already been
disrupted in NGC 5128's tidal field.
Description:
The Survey of Centaurus A's Baryonic Structures is an optical survey
of the nearby giant elliptical galaxy NGC5128 (Centaurus A) using the
Dark Energy Camera. This work focussed on identifying globular cluster
candidates of 22 sq. degrees centred on NGC5128. In doing so we
produced a list of ∼4.4x105 point, and point-like sources in the
optical u'g'r'i'z' bands with 50/90% completeness limits of at least
24.08/23.62, 22.67/22.27, 22.46/22.00, 22.05/21.63, and 21.71/21.34 AB
mags, respectively. The same data is also included for a list of ∼3000
highly probable globular cluster candidates Positional data is
typically accurate to at least 0.5".
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 54 438949 Point and point-like sources photometry
table3.dat 74 438949 Point and point-like sources photometric errors
table4.dat 105 3210 Globular cluster candidates photometry
table5.dat 93 3210 Globular cluster candidates photometric errors
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See also:
J/AJ/143/84 : New candidate globular clusters in NGC 5128 (Harris+, 2012)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 h RAh Right ascension (J2000)
4- 5 I2 min RAm Right ascension (J2000)
7- 11 F5.2 s RAs Right ascension (J2000)
13 A1 --- DE- Declination sign (J2000)
14- 15 I2 deg DEd Declination (J2000)
17- 18 I2 arcmin DEm Declination (J2000)
20- 24 F5.2 arcsec DEs Declination (J2000)
26- 30 F5.2 mag umag u-band apparent magnitude
32- 36 F5.2 mag gmag g-band apparent magnitude
38- 42 F5.2 mag rmag r-band apparent magnitude
44- 48 F5.2 mag imag i-band apparent magnitude
50- 54 F5.2 mag zmag z-band apparent magnitude
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 h RAh Right ascension (J2000)
4- 5 I2 min RAm Right ascension (J2000)
7- 11 F5.2 s RAs Right ascension (J2000)
13 A1 --- DE- Declination sign (J2000)
14- 15 I2 deg DEd Declination (J2000)
17- 18 I2 arcmin DEm Declination (J2000)
20- 24 F5.2 arcsec DEs Declination (J2000)
26- 29 F4.2 mag e_umag Statistical error on u-band magnitude
31- 34 F4.2 mag s_umag Systematic error on u-band magnitude
36- 39 F4.2 mag e_gmag Statistical error on g-band magnitude
41- 44 F4.2 mag s_gmag Systematic error on g-band magnitude
46- 49 F4.2 mag e_rmag Statistical error on r-band magnitude
51- 54 F4.2 mag s_rmag Systematic error on r-band magnitude
56- 59 F4.2 mag e_imag Statistical error on i-band magnitude
61- 64 F4.2 mag s_imag Systematic error on i-band magnitude
66- 69 F4.2 mag e_zmag Statistical error on z-band magnitude
71- 74 F4.2 mag s_zmag Systematic error on z-band magnitude
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- T17ID Homogenized designation, T17-NNNN
10- 30 A21 --- oldID Older designations (1)
32- 33 I2 h RAh Right ascension (J2000)
35- 36 I2 min RAm Right ascension (J2000)
38- 42 F5.2 s RAs Right ascension (J2000)
44 A1 --- DE- Declination sign (J2000)
45- 46 I2 deg DEd Declination (J2000)
48- 49 I2 arcmin DEm Declination (J2000)
51- 55 F5.2 arcsec DEs Declination (J2000)
57- 61 F5.2 --- Prob Confidence of being true GC
63- 68 F6.2 arcmin Rgc Angular distance from NGC5128
70- 75 F6.2 deg PA Position angle from NGC5128 (N of E)
77- 81 F5.2 mag umag u-band apparent magnitude
83- 87 F5.2 mag gmag g-band apparent magnitude
89- 93 F5.2 mag rmag r-band apparent magnitude
95- 99 F5.2 mag imag i-band apparent magnitude
101-105 F5.2 mag zmag z-band apparent magnitude
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Note (1): lists former IDs (GCNNNN) and/or those reported in Harris et al.
(2012, Cat J/AJ/143/84, arbitrarily numbered H12-NNN).
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- T17ID Homogenized designation, T17-NNNN
10- 11 I2 h RAh Right ascension (J2000)
13- 14 I2 min RAm Right ascension (J2000)
16- 20 F5.2 s RAs Right ascension (J2000)
22 A1 --- DE- Declination sign (J2000)
23- 24 I2 deg DEd Declination (J2000)
26- 27 I2 arcmin DEm Declination (J2000)
29- 33 F5.2 arcsec DEs Declination (J2000)
35- 39 F5.2 mag e_umag ?=-1 Statistical error on u-band magnitude
41- 45 F5.2 mag s_umag ?=-1 Systematic error on u-band magnitude
47- 51 F5.2 mag e_gmag ?=-1 Statistical error on g-band magnitude
53- 57 F5.2 mag s_gmag ?=-1 Systematic error on g-band magnitude
59- 63 F5.2 mag e_rmag ?=-1 Statistical error on r-band magnitude
65- 69 F5.2 mag s_rmag ?=-1 Systematic error on r-band magnitude
71- 75 F5.2 mag e_imag ?=-1 Statistical error on i-band magnitude
77- 81 F5.2 mag s_imag ?=-1 Systematic error on i-band magnitude
83- 87 F5.2 mag e_zmag ?=-1 Statistical error on z-band magnitude
89- 93 F5.2 mag s_zmag ?=-1 Systematic error on z-band magnitude
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Acknowledgements:
Matthew Alan Taylor, mtaylor(at)gemini.edu
(End) Matthew Taylor [Gemini Observatory], Patricia Vannier [CDS] 11-Jan-2018