J/A+A/640/A66 Updated X-ray view of the Hyades cluster (Freund+, 2020)
Updated X-ray view of the Hyades cluster.
Freund S., Robrade J., Schneider P.C., Schmitt J.H.M.M.
<Astron. Astrophys. 640, A66 (2020)>
=2020A&A...640A..66F 2020A&A...640A..66F (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; X-ray sources ; Stars, dwarfs ;
Cross identifications
Keywords: open clusters and associations: individual: Hyades - X-rays: stars -
stars: activity - stars: rotation - stars: coronae - stars: late-type
Abstract:
We revisit the X-ray properties of the main sequence Hyades members
and the relation between X-ray emission and stellar rotation.
As an input catalog for Hyades members, we combined three recent
membership lists derived from Gaia DR2 data that include the Hyades
core and its tidal tails. We searched for X-ray detections of the main
sequence Hyades members in the ROSAT all-sky survey (RASS), and
pointings from ROSAT, the Chandra X-Ray Observatory, and XMM-Newton.
Furtmermore, we adopted rotation periods derived from Kepler's K2
mission and other resources.
We find an X-ray detection for 281 of 1066 bona fide main sequence
Hyades members and provide statistical upper limits for the undetected
sources. The majority of the X-ray detected stars are located in the
Hyades core because of its generally smaller distance to the sun. F-
and G-type stars have the highest detection fraction (72%), while K-
and M-type dwarfs have lower detection rates (22 %). The X-ray
luminosities of the detected members range from about 2x1027 for
late M-type dwarfs to approximately 2x1030erg/s for active binaries.
The X-ray luminosity distribution functions formally differ for the
members in the core and tidal tails, which is likely caused by a
larger fraction of field stars in our Hyades tails sample. Compared to
previous studies, our sample is slightly fainter in X-rays due to
differences in the Hyades membership list used; furthermore, we extend
the X-ray luminosity distribution to fainter luminosities. The X-ray
activity of F- and G-type stars is well defined at FX/Fbol=10-5.
The fractional X-ray luminosity and its spread increases to later
spectral types reaching the saturation limit (FX/Fbol=10-3) for
members later than spectral type M3. Confirming previous results, the
X-ray flux varies by less than a factor of three between epochs for
the 104 Hyades members with multiple epoch data, significantly less
than expected from solar-like actvity cycles. Rotation periods are
found for 204 Hyades members, with about half of them being detected
in X-rays. The activity-rotation relation derived for the coeval
Hyades members has properties very similar to those obtained by other
authors investigating stars of different ages.
Description:
Our Hyades membership list is presented together with the X-ray and
rotational properties. The X-ray properties were obtained by a
crossmatch with detections from the Second ROSAT all-sky survey (2RXS,
Cat. J/A+A/588/A103) source catalog, and pointings from the Second
ROSAT PSPC catalog (2RXP, Cat. IX/30),
ROSAT HRI Pointed Observations (1RXH, Cat. IX/28), the Chandra Source
Catalog, and XMM-Newton. For sources with multiple detections, the
X-ray data derived from XMM-Newton or Chandra data is adopted as best
X-ray identification if available, and otherwise the ROSAT observation
with the longest exposure time. In addition to the best X-ray
identification, all detections from the different instruments are
provided. Hyades members with multiple detections of the same source
in one catalog have multiple entries in the table. All X-ray fluxes
are converted into the XMM-Newton band (0.2-12keV) adopting an APEC
thermal plasma model with a temperature of log(T)=6.5 and solar
metallicity. For the Hyades members not detected in any catalog, upper
limits are provided. The rotation periods are adopted from Douglas et
al. (2019ApJ...879..100D 2019ApJ...879..100D) and Lanzafame et al. (2018A&A...616A..16L 2018A&A...616A..16L,
Cat. I/345).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
hyades.dat 986 1205 Hyades membership list with X-ray properties
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See also:
IX/28 : ROSAT HRI Pointed Observations (1RXH (ROSAT Team, 2000)
IX/30 : Second ROSAT PSPC catalog (ROSAT, 2000)
IX/57 : The Chandra Source Catalog (CSC), Release 2.0 (Evans+, 2019)
J/A+A/623/A35 : A 3D view of the Hyades population (Lodieu+, 2019)
J/A+A/621/L2 : Hyades tidal tails revealed by Gaia DR2 (Roeser+, 2019)
J/A+A/621/L3 : Hyades tidal tails with Gaia DR2 (Meingast+, 2019)
J/A+A/588/A103 : Second ROSAT all-sky survey (2RXS) source catalog
(Boller+, 2016)
Byte-by-byte Description of file: hyades.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Catalog [LRM] Catalog of membership
(Catalog) (1)
5- 23 I19 --- GaiaDR2 Source ID in Gaia DR2 (Gaia_ID)
25- 44 F20.16 deg RAdeg Right ascension (ICRS) at Ep=2015.5
(RAdeg)
46- 66 F21.17 deg DEdeg Declination (ICRS) at Ep=2015.5 (DEdeg)
68- 86 F19.16 mas plx Parallax (plx)
88-107 F20.18 mas e_plx Error of the parallax (e_plx)
109-127 F19.16 mag Gmag Gaia G band magnitude (Gmag)
129-148 F20.16 mag BPmag ? Gaia BP band magnitude (BPmag)
150-169 F20.16 mag RPmag ? Gaia RP band magnitude (RPmag)
171-190 F20.16 pc Distcore Distance to Hyades core (Dist_core)
192-195 A4 --- Member [Core Tail] Member of core or tail
(Member)
197 A1 --- MS [M] Main sequence source (Main-seq)
199-208 A10 --- Xraycat Catalog of the best X-ray detection or
upper limit (X-ray_catalog)
210-231 F22.17 arcsec SepX-ray ? Angular separation between Hyades
member and best X-ray detection
(Sep_X-ray)
233-256 A24 --- X-rayID ID of best X-ray detection (X-ray_ID)
258-277 F20.16 arcsec PosErrXray ? Positional error of best detection
(PosErr_X-ray)
279-300 F22.18 ZW LX Best X-ray luminosity (LX)
302-323 F22.18 ZW e_LX ? Error of best X-ray luminosity (e_LX)
325 A1 --- r_Per Source of the best rotation period
(Period_Source) (2)
327-347 F21.17 d Per ? Best rotation period (Period)
349-368 F20.16 arcsec Sep2RXS ? Angular separation between Hyades
member and 2RXS counterpart (Sep_2RXS)
370-390 A21 --- 2RXSID ID of 2RXS counterpart (2RXS_ID)
392-411 F20.16 arcsec PosErr2RXS ? Position error of 2RXS counterpart
(PosErr_2RXS)
413-434 F22.18 ct/s Rate2RXS ? Count rate of 2RXS counterpart
(Rate_2RXS)
436-458 F23.19 ct/s e_Rate2RXS ? Error of count rate for 2RXS
counterpart (eRate2RXS)
460-477 F18.14 s ExpTime2RXS ? Exposure time of 2RXS counterpart
(ExpTime_2RXS)
479-498 F20.16 ZW LX2RXS ? 2RXS X-ray luminosity (LX_2RXS)
500-520 F21.17 ZW e_LX2RXS ? Error of 2RXS X-ray luminosity
(eLX2RXS)
522-541 F20.16 arcsec Sep2RXP ? Angular separation between Hyades
member and 2RXP counterpart (Sep_2RXP)
543-563 A21 --- 2RXPID ID of 2RXP counterpart (2RXP_ID)
565-569 F5.1 arcsec PosErr2RXP ? Position error of 2RXP counterpart
(PosErr_2RXP)
571-580 F10.6 ct/s Rate2RXP ? Count rate of 2RXP counterpart
(Rate_2RXP)
582-591 F10.6 ct/s e_Rate2RXP ? Error of count rate for 2RXP
counterpart (eRate2RXP)
593-599 F7.1 s ExpTime2RXP ? Exposure time of 2RXP counterpart
(ExpTime_2RXP)
601-621 F21.17 ZW LX2RXP ? 2RXP X-ray luminosity (LX_2RXP)
623-644 F22.18 ZW e_LX2RXP ? Error of 2RXP X-ray luminosity
(eLX2RXP)
646-665 F20.16 arcsec Sep1RXH ? Angular separation between Hyades
member and 1RXH counterpart (Sep_1RXH)
667-687 A21 --- 1RXHID ID of 1RXH counterpart (1RXH_ID)
689-693 F5.1 arcsec PosErr1RXH ? Position error of 1RXH counterpart
(PosErr_1RXH)
695-704 F10.6 ct/s Rate1RXH ? Count rate of 1RXH counterpart
(Rate_1RXH)
706-715 F10.6 ct/s e_Rate1RXH ? Error of count rate for 1RXH
counterpart (eRate1RXH)
717-723 F7.1 s ExpTime1RXH ? Exposure time of 1RXH counterpart
(ExpTime_1RXH)
725-744 F20.16 ZW LX1RXH ? 1RXH X-ray luminosity (LX_1RXH)
746-766 F21.17 ZW e_LX1RXH ? Error of 1RXH X-ray luminosity
(eLX1RXH)
768-776 I9 --- obsIDXMM ? Observation ID of XMM counterpart
(obsID_XMM)
778-799 F22.18 ZW LXXMM ? XMM X-ray luminosity (LX_XMM)
801-822 F22.18 ZW e_LXXMM ? Error of XMM X-ray luminosity
(eLXXMM)
824-844 F21.17 arcsec SepChandra ? Angular separation between Hyades
member and Chandra counterpart
(Sep_Chandra)
847-867 A21 --- ChandraID ID of Chandra counterpart (Chandra_ID)
869-874 F6.2 arcsec PosErrChandra ? Position error of Chandra counterpart
(PosErr_Chandra)
876-896 E21.16 mW/m2 FluxChandra ? Chandra X-ray flux (Flux_Chandra)
898-919 E22.17 mW/m2 e_FluxChandra ? Lower limit of Chandra X-ray flux
(lolimFluxChandra)
921-942 E22.17 mW/m2 E_FluxChandra ? Upper limit of Chandra X-ray flux
(hilimFluxChandra)
944-964 F21.17 ZW LXChandra ? Chandra X-ray luminosity (LX_Chandra)
966-986 F21.17 ZW e_LXChandra ? Error of Chandra X-ray luminosity
(eLXChandra)
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Note (1): References as follows:
L = Lodieu et al. (2019, Cat. J/A+A/623/A35)
R = Roeser et al. (2019. Cat. J/A+A/621/L2)
M = Meingast & Alves (2019. Cat. J/A+A/621/L3)
Note (2): References as follows:
2 = K2 Campaign 4 from Douglas et al. (2016, Cat. J/ApJ/822/47)
3 = K2 Campaign 13 from Douglas et al. (2019ApJ...879..100D 2019ApJ...879..100D)
P = Prosser et al. (1995PASP..107..211P 1995PASP..107..211P)
H = Hartman et al. (2011, Cat. J/AJ/141/166)
D = Delorme et al. (2011, Cat. J/MNRAS/413/2218)
K = ASAS Rotational Period
R = Radick et al. (1987ApJ...321..459R 1987ApJ...321..459R, 1995ApJ...452..332R 1995ApJ...452..332R)
L = Lanzafame et al. (2018A&A...616A..16L 2018A&A...616A..16L, Cat. I/345)
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Acknowledgements:
Sebastian Freund, sebastian.freund(at)uni-hamburg.de
(End) Patricia Vannier [CDS] 25-Jun-2020