J/MNRAS/518/1505 HST photometry of NGC 1850 (Kamann+, 2023)
The effects of stellar rotation along the main sequence of the 100-Myr-old
massive cluster NGC 1850.
Kamann S., Saracino S., Bastian N., Gossage S., Usher C., Baade D.,
Cabrera-Ziri I., de Mink S.E., Ekstrom S., Georgy C., Hilker M.,
Larsen S.S., Mackey D., Niederhofer F., Platais I., Yong D.
<Mon. Not. R. Astron. Soc. 518, 1505-1521 (2023)>
=2023MNRAS.518.1505K 2023MNRAS.518.1505K (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Stars, early-type ; Photometry, HST ;
Spectroscopy ; Ultraviolet
Keywords: stars: rotation - Hertzsprung-Russell and colour-magnitude diagrams -
galaxies: star clusters: individual: NGC 1850
Abstract:
Young star clusters enable us to study the effects of stellar rotation
on an ensemble of stars of the same age and across a wide range in
stellar mass and are therefore ideal targets for understanding the
consequences of rotation on stellar evolution. We combine MUSE
spectroscopy with HST photometry to measure the projected rotational
velocities (Vsini) of 2184 stars along the split main sequence and on
the main sequence turn-off (MSTO) of the 100Myr-old massive
(105M☉) star cluster NGC 1850 in the Large Magellanic Cloud.
At fixed magnitude, we observe a clear correlation between Vsini and
colour, in the sense that fast rotators appear redder. The average
Vsini values for stars on the blue and red branches of the split main
sequence are ∼100km/s and ∼200km/s, respectively. The values
correspond to about 25-30% and 50-60% of the critical rotation
velocity and imply that rotation rates comparable to those observed in
field stars of similar masses can explain the split main sequence. Our
spectroscopic sample contains a rich population of ∼200 fast rotating
Be stars. The presence of shell features suggests that 23% of them are
observed through their decretion disks, corresponding to a disk
opening angle of 15 degrees. These shell stars can significantly alter
the shape of the MSTO, hence care should be taken when interpreting
this photometric feature. Overall, our findings impact our
understanding of the evolution of young massive clusters and provide
new observational constraints for testing stellar evolutionary models.
Description:
We provide the photometry of NGC 1850 obtained with the Hubble Space
Telescope as well as the combined MUSE spectra for all stars in our
spectroscopic sample.
Objects:
----------------------------------------------------
RA (2000) DE Designation(s)
----------------------------------------------------
05 08 50.19 -68 45 35.7 NGC 1850 = ESO 56-70
----------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
ngc1850.dat 142 63197 The HST photometry for NGC 1850
list.dat 57 3441 List of fits spectra
fits/* . 3441 Individual fits spectra
--------------------------------------------------------------------------------
Byte-by-byte Description of file: ngc1850.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 I7 --- Id Unique identifier for each source (1)
9- 25 F17.14 deg RAdeg Right Ascension (J2000.0)
27- 44 F18.14 deg DEdeg Declination (J2000.0)
46- 51 F6.3 mag F275w ? HST/WFC3 UVIS F275W magnitude (Vega)
53- 57 F5.3 mag e_F275w ? Uncertainty of F275W magnitude
59- 64 F6.3 mag F336w ? HST/WFC3 UVIS F336W magnitude (Vega)
66- 70 F5.3 mag e_F336w ? Uncertainty of F336W magnitude
72- 77 F6.3 mag F343n ? HST/WFC3 UVIS F343N magnitude (Vega)
79- 83 F5.3 mag e_F343n ? Uncertainty of F343N magnitude
85- 90 F6.3 mag F438w ? HST/WFC3 UVIS F438W magnitude (Vega)
92- 96 F5.3 mag e_F438w ? Uncertainty of F438W magnitude
98-103 F6.3 mag F656n ? HST/WFC3 UVIS F656N magnitude (Vega)
105-109 F5.3 mag e_F656n ? Uncertainty of F656N magnitude
111-116 F6.3 mag F814w ? HST/WFC3 UVIS F814W magnitude (Vega)
118-122 F5.3 mag e_F814w ? Uncertainty of F814W magnitude
124-142 I19 --- GaiaEDR3 ? Source ID in Gaia EDR3 (where available)
--------------------------------------------------------------------------------
Note (1): Sources with IDs >200,000 and <1,000,000 are undetected in the HST
data, but available in Gaia EDR3.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 I7 --- Id Unique identifier for each source
9- 12 I4 --- Nx Number of pixels along X-axis
14- 17 I4 0.1nm bAWAV Lower value of wavelength interval
19- 25 F7.2 0.1nm BAWAV Upper value of wavelength interval
27- 30 F4.2 0.1nm dAWAV ? Wavelength resolution
32- 33 I2 Kibyte size Size of FITS file
35- 57 A23 --- FileName Name of FITS file, in subdirectory fits
--------------------------------------------------------------------------------
Acknowledgements:
S. Kamann, s.kamann(at)ljmu.ac.uk
(End) Patricia Vannier [CDS] 02-Nov-2022