J/MNRAS/503/292 NIR photometry of the core of R136 (Khorrami+, 2021)
High-contrast and resolution near-infrared photometry of the core of R136.
Khorrami Z., Langlois M., Clark P.C., Vakili F., Buckner A.S.M.,
Gonzalez M., Crowther P., Wunsch R., Palous J., Lumsden S., Moraux E.
<Mon. Not. R. Astron. Soc., 503, 292-311 (2021)>
=2021MNRAS.503..292K 2021MNRAS.503..292K (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Photometry, infrared
Keywords: instrumentation: adaptive optics -
stars: luminosity function, mass function - stars: massive -
open clusters and associations: individual: R136
Abstract:
We present the sharpest and deepest near-infrared photometric analysis
of the core of R136, a newly formed massive star cluster at the centre
of the 30 Doradus star-forming region in the Large Magellanic Cloud.
We used the extreme adaptive optics of the SPHERE focal instrument
implemented on the ESO Very Large Telescope and operated in its IRDIS
imaging mode for the second time with longer exposure time in the H
and K filters. Our aim was to (i) increase the number of resolved
sources in the core of R136, and (ii) to compare with the first epoch
to classify the properties of the detected common sources between the
two epochs. Within the field of view (FOV) of 10.8"x12.1"
(2.7pc*3.0pc), we detected 1499 sources in both H and K filters, for
which 76 per cent of these sources have visual companions closer than
0.2". The larger number of detected sources enabled us to better
sample the mass function (MF). The MF slopes are estimated at ages of
1, 1.5, and 2Myr, at different radii, and for different mass ranges.
The MF slopes for the mass range of 10-300M☉ are about 0.3dex
steeper than the mass range of 3-300M☉, for the whole FOV and
different radii. Comparing the JHK colours of 790 sources common in
between the two epochs, 67 per cent of detected sources in the outer
region (r>3") are not consistent with evolutionary models at 1-2Myr
and with extinctions similar to the average cluster value, suggesting
an origin from ongoing star formation within 30 Doradus, unrelated to
R136.
Description:
We presented a new photometric analysis of the core of R136 using the
second epoch data from VLT/SPHERE instrument in the near-IR. We
observed R136 in H and K filters in better atmospheric observing
conditions and longer exposure time than the first epoch. This enabled
us to detect twice as many sources (in H and K) as we have detected in
the first epoch (in J and K) in the FOV of IRDIS (10.8"x12.1")
covering almost 2.7x3.0pc of R136 core. Among 1658 and 2528 detected
sources in H and K, respectively, we found 1499 common sources between
these two sets of data, where 76 per cent of these sources have visual
companion closer than 0.2", which is higher than the value found in
the first epoch in 2015 data (Khorrami et al., 2017A&A...602A..56K 2017A&A...602A..56K,
Cat. J/A+A/602/A56). About 71 per cent of the newly detected sources
are located in the outer region (r>3") of the cluster.
Objects:
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RA (2000) DE Designation(s)
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05 38 42.39 -69 06 03.3 R136 = RMC 136
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 115 55 List of brightest spectroscopically known stars
in the core of R136 studied in optical
tablea2.dat 58 138 List of detected sources in the centre of
R136 brighter than 16mag in K
tablea3.dat 61 1499 List of detected sources in H and K data in 2018
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See also:
J/ApJ/448/179 : HST photometry in R136 (Hunter+ 1995)
J/A+A/602/A56 : R136 JKs photometry from VLT/SPHERE EAO (Khorrami+, 2017)
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- HSH95 Identification number in Hunter et al.
(1995ApJ...448..179H 1995ApJ...448..179H, Cat. J/ApJ/448/179),
[HSH95] NNNN in Simbad
5- 6 A2 --- WB85 Name in Weigelt & Baier (1985A&A...150L..18W 1985A&A...150L..18W),
RMC 136aN in Simbad
8- 10 I3 --- IDK Star identification in the
SPHERE/IRDIS/K-band catalogue
12- 16 F5.2 mag Kmag18 SPHERE IRDIS K magnitude in 2018
(error ±0.01)
18- 22 F5.2 mag Hmag18 SPHERE IRDIS H magnitude in 2018
(error ±0.01)
24- 28 F5.2 mag Jmag15 SPHERE IRDIS J magnitude in 2015
(error ±0.13)
30- 33 F4.2 arcsec r Distance from r136a1 in our K data
35- 38 F4.1 K Teff Effective temperature
40- 43 F4.1 K e_Teff Effective temperature error
44- 49 A6 --- r_Teff Reference for Teff if not from Bestenlehner
et al., 2014A&A...570A..38B 2014A&A...570A..38B (1)
50- 53 F4.2 [Lsun] logL Luminosity
55- 58 F4.2 [Lsun] E_logL Luminosity error (upper value)
60- 63 F4.2 [Lsun] e_logL Luminosity error (lower value)
64- 69 A6 --- r_logL Reference for logL if not from Bestenlehner
et al., 2014A&A...570A..38B 2014A&A...570A..38B (1)
70- 72 F3.1 [cm/s2] logg ?=- Surface gravity from Bestenlehner et al.,
2014A&A...570A..38B 2014A&A...570A..38B
74- 76 I3 Msun Mini ?=- Stellar initial mass estimated by fitting
grids of PARSEC evolutionary models
(0.1-10Myr) to the Teff and logL
78- 80 I3 Msun E_Mini ? Stellar initial mass error (upper value)
82- 83 I2 Msun e_Mini ? Stellar initial mass error (lower value)
85- 87 F3.1 Myr Age ?=- Age estimated by fitting grids of PARSEC
evolutionary models (0.1-10Myr)
to the Teff and logL
89- 91 F3.1 Myr E_Age ? Age error (upper value)
93- 95 F3.1 Myr e_Age ? Age error (lower value)
97-108 A12 --- SpType Spectral type
110-115 A6 --- r_SpType Reference for SpType if not from Bestenlehner
et al., 2014A&A...570A..38B 2014A&A...570A..38B (1)
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Note (1): References as follows:
[MH98] = Massey & Hunter (1998ApJ...493..180M 1998ApJ...493..180M)
[CD98] = Crowther & Dessart (1998MNRAS.296..622C 1998MNRAS.296..622C)
[C10] = Crowther et al. (2010MNRAS.408..731C 2010MNRAS.408..731C)
[B14] = Bestenlehner et al. (2014A&A...570A..38B 2014A&A...570A..38B)
[C16] = Crowther et al. (2016MNRAS.458..624C 2016MNRAS.458..624C)
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Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- IDK Star identification in the
SPHERE/IRDIS/K-band catalogue
5- 9 F5.2 mag Kmag18 K band magnitude in 2018
11- 15 F5.2 mag Hmag18 H band magnitude in 2018
17- 21 F5.2 mag Kmag15 K band magnitude in 2015
23- 27 F5.2 mag Jmag15 Jband magnitude in 2015
29- 31 I3 --- HSH95 Identification number in Hunter et al.
(1995ApJ...448..179H 1995ApJ...448..179H, Cat. J/ApJ/448/179),
[HSH95] NNNN in Simbad
33- 34 A2 --- WB85 Name in Weigelt & Baier (1985A&A...150L..18W 1985A&A...150L..18W),
RMC 136aN in Simbad
36- 40 F5.2 mag Umag ?=99.99 F336W (U) magnitude
42- 46 F5.2 mag Vmag F555W (V) magnitude
48- 52 F5.2 mag Imag F814W (I) magnitude
54- 58 F5.2 mag V-K F555W-Kmag18 (V-K) colour index
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Byte-by-byte Description of file: tablea3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- IDK [1/2512] Star identification in the
SPHERE/IRDIS/K-band catalogue
6- 11 F6.2 pix X X position
13- 16 F4.2 pix e_X X position error
18- 24 F7.2 pix Y Y position
26- 29 F4.2 pix e_Y Y position error
31- 35 F5.2 mag Kmag18 K band magnitude in 2018
37- 40 F4.2 mag e_Kmag18 K band magnitude in 2018 error
42- 45 F4.2 --- Kcor Correlation between the PSF of detected source
with the reference PSF in K image
47- 51 F5.2 mag Hmag18 H band magnitude in 2018
53- 56 F4.2 mag e_Hmag18 H band magnitude in 2018 error
58- 61 F4.2 --- Hcor Correlation between the PSF of detected source
with the reference PSF in H image
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 24-Nov-2023