J/A+A/653/A133 GALACTICNUCLEUS IV. JHKs imaging survey (Nogueras-Lara+, 2021)
GALACTICNUCLEUS:
A high-angular-resolution JHKs imaging survey of the Galactic centre.
IV. Extinction maps and de-reddened photometry.
Nogueras-Lara F., Schoedel R., Neumayer N.
<Astron. Astrophys. 653, A133 (2021)>
=2021A&A...653A.133N 2021A&A...653A.133N (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Galactic center ; Photometry, infrared ; Extinction
Keywords: Galaxy: centre - Galaxy: bulge - Galaxy: structure -
stars: horizontal-branch - dust, extinction
Abstract:
The extreme extinction (AV∼30mag) and its variation on arc-second
scales towards the Galactic centre hamper the study of its stars.
Their analysis is restricted to the near infrared (NIR) regime, where
the extinction curve can be approximated by a broken power law for the
JHKs bands. Therefore, correcting for extinction at these wavelengths
is fundamental to analyse the structure and stellar population of the
central regions of our Galaxy. We aim at: (1) Discussing different
strategies to de-redden the photometry and checking the usefulness of
extinction maps to deal with variable stars. (2) Building and making
publicly available extinction maps for the NIR bands JHKs. (3)
Creating a de-reddened catalogue of the GALACTICNUCLEUS (GNS) survey,
identifying foreground stars. (4) Performing a preliminary analysis of
the de-reddened $K_s$ luminosity functions (KLFs). We use photometry
from the GNS survey to create extinction maps for the whole catalogue.
We take red clump (RC) and red giant stars of similar brightness as a
reference to build the maps, and de-redden the GNS photometry. We
discuss the limitations of the process and analyse non-linear effects
of the de-reddening. We create high resolution (∼3'') extinction maps
with low statistical and systematics uncertainties (≲5%), and compute
average extinctions for each of the regions covered by the GNS. We
check that our maps effectively correct the differential extinction
reducing the spread of the RC features by a factor of ∼2. We assess
the validity of the broken power law approach computing two equivalent
extinction maps AH using either JH and HKs photometry for the same
reference stars, and obtain compatible average extinctions within the
uncertainties. Finally, we analyse de-reddened KLFs for different
line-of-sights and find that the regions belonging to the NSD contain
a homogeneous stellar population that is significantly different from
the one in the innermost bulge regions.
Description:
We include in electronic form the obtained extinction maps, the
catalogues corrected for duplications (Sect. 2.1), and the de-reddened
ones specified in Sect. 5.2 of the manuscript.
(1) Extinction maps:
We used a two-layers extinction map approach. For each of the
GALACTICNUCLEUS regions (Central, NSD E, NSD W, T E, T W, IBS, and
IBN), we include 4 maps. Two of them corresponding to the first
extinction layer and the JH bands (computed using JH photometry), and
two more for the HKs bands (using HKs photometry). We also include 2
extinction maps corresponding to the second layer of extinction and
the H and Ks bands (obtained using HKs photometry), for all the
GALACTICNUCLEUS regions except the IBS and IBN. The associated
uncertainty maps are also made publicly available. The units of all
the maps correspond to the magnitudes in the given band (J, H, and
Ks). All the maps are astrometrically calibrated using the
GALACTICNUCLEUS survey as a reference.
Files are named ("u" if the map is an uncertainty map) + "band" +
"extinction layer" + "bands used to compute the map" + _ +
"GALACTICNUCLEUS region" + .fit
The GALACTICNUCLEUS regions are indicates as:
- Central: "C"
- NSD E: "NE"
- NSD w: "NW"
- T E: "TE"
- T W: "TW"
- IBS: "BS"
- IBN: "BN"
As an example:
-J1JH_C.fit -> correspond to the J extinction map for central region,
and the first extinction, layer computed using JH photometry.
-uJ1JH_C.fit -> This is the extinction map associated to the previous
one.
(2) Catalogues corrected for duplicated:
Catalogues specified in Sect 2.1 of the manuscript. This is 7
catalogues for the different regions covered by the GALACTICNUCLEUS
catalogue: Central, NSD East, NSD West, Transition East, Transition
West, Inner Bulge North and Inner Bulge South. The catalogues follow
the structure presented in Table 2 of Nogueras-Lara et al. (2019, Cat.
J/A+A/631/A20).
(3) De-reddened catalogues:
Catalogues specified in Sect 5.2 of the manuscript. This is 7
catalogues for the different regions covered by the GALACTICNUCLEUS
catalogue: Central, NSD East, NSD West, Transition East, Transition
West, Inner Bulge North and Inner Bulge South. The catalogues follow
the structure presented in Table 3.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
central.dat 236 2009482 Central region catalog
cen-nd.dat 242 2009482 Central region catalog corrected for
duplicated sources
ibn.dat 236 90265 Inner Bulge North catalog
ibn-nd.dat 242 90265 Inner Bulge North catalog corrected for
duplicated sources
ibs.dat 236 159572 Inner Bulge South catalog
ibs-nd.dat 242 159572 Inner Bulge South catalog corrected for
duplicated sources
nsde.dat 236 488147 NSD East catalog
nsde-nd.dat 242 488147 NSD East catalog corrected for duplicated sources
nsdw.dat 236 199445 NSD West catalog
nsdw-nd.dat 242 199445 NSD West catalog corrected for duplicated sources
te.dat 236 162763 Transition East catalog
te-nd.dat 242 162763 Transition East catalog corrected for
duplicated sources
tw.dat 236 167972 Transition West catalog
tw-nd.dat 242 167972 Transition West catalog corrected for
duplicated sources
list.dat 147 76 List of fits maps
fits/* . 76 Individual fits maps
--------------------------------------------------------------------------------
See also:
J/A+A/610/A83 : GALACTICNUCLEUS I: JHKs imaging survey (Nogueras-Lara+, 2018)
J/A+A/631/A20 : GALACTICNUCLEUS II: JHKs imaging survey (Nogueras-Lara+, 2019)
Byte-by-byte Description of file: central.dat i??.dat nsd?.dat t?.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right ascension combining detections (J2000)
11- 21 F11.9 arcsec e_RAdeg Uncertainty on RA
23- 32 F10.6 deg DEdeg Declination combining detections (J2000)
34- 44 F11.9 arcsec e_DEdeg Uncertainty on DEC
46- 53 F8.5 mag Jmag ?=99 J-band magnitude (1)
55- 62 F8.5 mag e_Jmag ?=99 Uncertainty on J-band magnitude (1)
64- 71 F8.5 mag Hmag ?=99 H-band magnitude (1)
73- 80 F8.5 mag e_Hmag ?=99 Uncertainty on H-band magnitude (1)
82- 89 F8.5 mag Ksmag ?=99 Ks-band magnitude (1)
91- 98 F8.5 mag e_Ksmag ?=99 Uncertainty on Ks-band magnitude (1)
100-101 I2 --- FJH [-1/1] Detection as foreground population
in JH (2)
103-104 I2 --- FHK [-1/1] Detection as foreground population
in HK (2)
106-115 F10.5 mag AJ1JH ?=- J extinction for layer 1 computed from
JH (3)
117-126 F10.5 mag e_AJ1JH []?=- J extinction uncertainty for layer 1
computed from JH (3)
128-137 F10.5 mag AH1JH ?=- H extinction for layer 1 computed from
JH (3)
139-148 F10.5 mag e_AH1JH []?=- H extinction uncertainty for layer 1
computed from JH (3)
150-159 F10.5 mag AH1HK ?=- H extinction for layer 1 computed from
HKs (3)
161-170 F10.5 mag e_AH1HK []?=- H extinction uncertainty for layer 1
computed from HKs (3)
172-181 F10.5 mag AK1HK ?=- Ks extinction for layer 1 computed from
HKs (3)
183-192 F10.5 mag e_AK1HK []?=- Ks extinction uncertainty for layer 1
computed from HKs (3)
194-203 F10.5 mag AH2HK ?=- H extinction for layer 2 computed from
HKs (3)
205-214 F10.5 mag e_AH2HK []?=- H extinction uncertainty for layer 2
computed from HKs (3)
216-225 F10.5 mag AK2HK ?=- Ks extinction for layer 2 computed from
HKs (3)
227-236 F10.5 mag e_AK2HK []?=- Ks extinction uncertainty for layer 2
computed from HKs (3)
--------------------------------------------------------------------------------
Note (1): A magnitude value equals to 99 indicates that there is no detection
for a given source.
Note (2): Detection flag as follows:
1 = foreground population
-1 = target stars
Note (3): A value of -1 indicates a the star does not correspond to a given
layer. A value of 0 indicates a star too close to the borders of the
corresponding extinction map. A "---" value indicate that there is not any
associated value.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: *-nd.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right ascension combining detections (J2000)
(ra)
11- 21 F11.9 arcsec e_RAdeg Uncertainty on RA (dra)
23- 32 F10.6 deg DEdeg Declination combining detections (J2000)
(dec)
34- 44 F11.9 arcsec e_DEdeg Uncertainty on DE (ddec)
46- 54 F9.5 deg RAJdeg ?=0 Right ascension J-band detection (J2000)
(raJ) (1)
56- 66 F11.9 arcsec e_RAJdeg ?=0 Uncertainty on RAJ (draJ)
68- 77 F10.6 deg DEJdeg ?=0 Declination J-band detection (J2000)
(decJ) (1)
79- 89 F11.9 arcsec e_DEJdeg ?=0 Uncertainty on DEJ (ddecJ)
91- 99 F9.5 deg RAHdeg ?=0 Right ascension H-band detection (J2000)
(raH) (1)
101-111 F11.9 arcsec e_RAHdeg ?=0 Uncertainty on RAH (draH)
113-122 F10.6 deg DEHdeg ?=0 Declination H-band detection (J2000)
(decH) (1)
124-134 F11.9 arcsec e_DEHdeg ?=0 Uncertainty on DEH (ddecH)
136-144 F9.5 deg RAKsdeg ?=0 Right ascension Ks-band detection
(J2000) (raKs) (1)
146-156 F11.9 arcsec e_RAKsdeg ?=0 Uncertainty on RAKs (draKs)
158-167 F10.6 deg DEKsdeg Declination Ks-band detection (J2000)
(decKs) (1)
169-179 F11.9 arcsec e_DEKsdeg ?=0 Uncertainty on DEKs (ddecKs)
181-188 F8.5 mag Jmag ?=99 J-band magnitude (J) (2)
190-197 F8.5 mag e_Jmag ?=99 Uncertainty on J-band magnitude (dJ)
199-206 F8.5 mag Hmag ?=99 H-band magnitude (H) (2)
208-215 F8.5 mag e_Hmag ?=99 Uncertainty on H-band magnitude (dH)
217-224 F8.5 mag Ksmag ?=99 Ks-band magnitude (Ks) (2)
226-233 F8.5 mag e_Ksmag ?=99 Uncertainty on Ks-band magnitude (dKs)
235-236 I2 --- iJ J-band detection in iJ pointings (iJ) (3)
238-239 I2 --- iH H-band detection in iH pointings (iH) (3)
241-242 I2 --- iKs Ks-band detection in iKs pointings (iKs) (3)
--------------------------------------------------------------------------------
Note (1): A coordinate value equals to zero means that a star was not detected
in a given band.
Note (2): A magnitude value equals to 99 indicates that there is no detection
for a given source.
Note (3): iJ, iH and iKs indicate the number of fields where a star were
detected to obtain its final photometry. A value of -1 indicates that the star
was a duplicated source.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 25 F6.4 arcsec/pix scale Scale of the image
27- 31 I5 --- Nx Number of pixels along X-axis
33- 37 I5 --- Ny Number of pixels along Y-axis
39- 45 I7 Kibyte size Size of FITS file
47- 58 A12 --- FileName Name of FITS file, in subdirectory fits
60-147 A88 --- Title Title of the FITS file
--------------------------------------------------------------------------------
History:
From Francisco Nogueras-Lara, fnoguer(ay)iaa.es
Acknowledgements:
The research leading to these results has received funding from the
European Research Council under the European Union's Seventh Framework
Programme (FP7/2007-2013) / ERC grant agreement No [614922]. This
work is based on observations made with ESO Telescopes at the La Silla
Paranal Observatory under programmes IDs 195.B-0283 and 091.B-0418. We
thank the staff of ESO for their great efforts and helpfulness. Author
F N-L acknowledges financial support from the State Agency for
Research of the Spanish MCIU through the "Center of Excellence Severo
Ochoa" award for the Instituto de Astrofisica de Andalucia
(SEV-2017-0709). F N-L acknowledges financial support from a MECD
pre-doctoral contract, code FPU14/01700. F N acknowledges financial
support through Spanish grants ESP2015-65597-C4-1-R and
ESP2017-86582-C4-1-R (MINECO/FEDER). N.N. acknowledges support by
Sonderforschungsbereich SFB 881 'The Milky Way System' (subproject B8)
of the German Research Foundation (DFG).
References:
Nogueras-Lara F., Paper I 2018A&A...610A..83N 2018A&A...610A..83N, Cat. J/A+A/610/A83
Nogueras-Lara F., Paper II 2019A&A...631A..20N 2019A&A...631A..20N, Cat. J/A+A/631/A20
Nogueras-Lara F., Paper III 2020A&A...641A.141N 2020A&A...641A.141N
(End) Patricia Vannier [CDS] 05-Jul-2021