J/A+A/620/A55 Magnetic flaring from PMS stars spectra (Flaccomio+, 2018)
A multi-wavelength view of magnetic flaring from PMS stars.
Flaccomio E., Micela G., Sciortino S., Cody A.M., Guarcello M.G.,
Morales-Calderon M., Rebull L., Stauffer J.R.
<Astron. Astrophys. 620, A55 (2018)>
=2018A&A...620A..55F 2018A&A...620A..55F (SIMBAD/NED BibCode)
ADC_Keywords: Stars, pre-main sequence ; Spectra, optical ; Spectra, infrared ;
X-ray sources
Keywords: stars: activity - stars: coronae - stars: flare -
stars: pre-main sequence - stars: variables: T Tauri - HerbigAe/Be -
X-rays: stars
Abstract:
Flares from the Sun and other stars are most prominently observed in
the soft X-ray band. Most of the radiated energy, however, is released
at optical/UV wavelengths. In spite of decades of investigation, the
physics of flares is not fully understood. Even less is known about
the powerful flares routinely observed from pre-main sequence stars,
which might significantly influence the evolution of circumstellar
disks. Observations of the NGC2264 star forming region were obtained
in Dec. 2011, simultaneously with three telescopes, Chandra (X-rays),
CoRoT (optical), and Spitzer (mIR), as part of the "Coordinated
Synoptic Investigation of NGC2264" (CSI-NGC2264). Shorter Chandra and
CoRoT observations were also obtained in March 2008. We analyzed the
lightcurves to detect X-ray flares with an optical and/or mIR
counterpart. Basic flare properties from the three datasets, such as
emitted energies and peak luminosities, were then compared to
constrain the spectral energy distribution of the flaring emission and
the physical conditions of the emitting regions. Flares from stars
with and without circumstellar disks were also compared to establish
any difference that might be attributed to the presence of disks.
Seventy-eight X-ray flares with an optical and/or mIR counterpart were
detected. Their optical emission is found to correlate well with, and
to be significantly larger than, the X-ray emission. The slopes of the
correlations suggest that the difference becomes smaller for the most
powerful flares. The mIR flare emission seems to be strongly affected
by the presence of a circumstellar disk: flares from stars with disks
have a stronger mIR emission with respect to stars without disks. This
might be attributed to the reprocessing of the optical (and X-ray)
flare emission by the inner circumstellar disk, providing evidence for
flare-induced disk heating.
Description:
Tables are provided with the data to reproduce figure B.1. in the
paper, showing the lightcurves of flares observed simultaneously in
the Chandra X-ray band, and in the CoRoT (optical) and/or Spitzer
(mIR) bands. Up to four tables are included for each of the 75 panels
in the figure: the CoRoT lightcurve, the Spitzer lightcurve, and the
Chandra lightcurve, binned using both a fixed bin duration (indicated
in the File Summary below as "bin") and the "natural binning"
Maximum-Likelihood algorithm described in the text (indicated as
"blk"). For the CoRoT and Spitzer lightcurves, polynomial expressions
representing the non-flaring emission during flares, derived as
described in the text, are reported in the header of the relative text
files, along with time intervals used to derived time-integrated flare
emission.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 187 78 List of flares, deduced physical quantities,
and host-star properties
opt/* . 56 *Individual CoRoT spectra
mir/* . 36 *Individual Spitzer spectra
xbl/* . 74 Individual Chandra spectra "natural binning"
xbi/* . 75 Individual Chandra spectra fixed bin duration
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Note on opt/* and mir/*: Six header lines starting with '#' report the
polynomial fit representing the non-flaring flux during the flare, as well
as the column labels and units.
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See also:
J/AJ/138/1116 : A Spitzer view of NGC 2264 (Sung+, 2009)
J/AJ/147/82 : Monitoring of disk-bearing stars in NGC 2264 (Cody+, 2014)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Src Source number
5 A1 --- n_Src [*yzx] Note on Source (1)
7- 12 I6 --- Mon Idenfication number from Cody et al., 2014,
Cat. J/AJ/147/82, CSIMon-NNNNNN in Simbad
14- 24 A11 --- Obs Chandra observation id number(s) during
which the flare occurred
26- 30 F5.2 10+28J EX Total emitted X-ray energy (Chandra)
31 A1 --- u_EX Uncertainty flag on EX
33- 36 F4.2 10+25W LXpk ?=- Flare peak X-ray luminosity (Chandra)
37 A1 --- u_LXpk Uncertainty flag on LXpk
39- 43 F5.2 10+28J EOpt ?=- Optical energy (CoRoT)
44 A1 --- u_EOpt Uncertainty flag on EOpt
46- 50 F5.2 10+25W LOptpk ?=- Flare peak optical luminosity (CoRoT)
51 A1 --- u_LOptpk Uncertainty flag on LOptpk
53- 59 F7.2 10+28J EIR ?=- Infrared energy (Spitzer)
60 A1 --- u_EIR Uncertainty flag on EIR
62- 68 F7.2 10+25W LIRpk ?=- Flare peak infrared luminosity (Spitzer)
69 A1 --- u_LIRpk Uncertainty flag on LIRpk
71- 73 A3 --- Class Class
75- 79 F5.1 0.1nm EWHa ?=- Hα equivalent width
81- 84 F4.2 mag AV ?=- Absorption in V band
86- 90 F5.2 10+22cm-2 NH ?=- Hydrogen column density
93- 96 A4 --- SpType MK spectral type
98-102 F5.2 mag Vmag ?=- V magnitude
106-110 F5.2 mag Rmag ?=- R magnitude
114-118 F5.2 mag Imag ?=- I magnitude
120-122 A3 --- CoRoT CoRoT light curve type
123-128 F6.3 d Prot ? Rotational period
130-143 A14 --- FOpt FileName of optical spectrum,
in subdirectory opt
145-158 A14 --- FXbi FileName of Chandra spectrum fixed bin
duration, in subdirectory xbi
160-173 A14 --- FXbl FileName of Chandra spectrum
"natural binning", in subdirectory xbl
175-187 A13 --- FmIR FileName of Spitzer spectrum,
in subdirectory mir
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Note (1): Individual notes as follows:
* = Src 405: All energies and peak luminosities are considered highly
uncertain because of the large discrepancy between optical and X-ray
extinction estimates (Sect. 5).
y = Src 502: X-ray flare detected with 4.5 counts. No estimate of extinction
was possible since AV is not available and NH could not be derived from
the fit of the X-ray spectrum because of its low statistics.
z = Src 536: Classified as class III on the basis of the Sung et al. (2009,
Cat. J/AJ/138/1116) Spitzer photometry. Cody et al. (2014,
Cat. J/AJ/147/82) indicate, however, that the star has a mIR excess.
This is based on the MIPS 240m flux (not reported by Sung et al. 2009),
which is, however, strongly contaminated by a nearby YSO associated with
ACIS source No 541.
x = Src 713: The Chandra flare falls in the gap between the last two
observations - EX was multiplied by 1.497 to approximatively correct for
the missing exposure time.
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Byte-by-byte Description of file (#): opt/*
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Bytes Format Units Label Explanations
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4- 15 F12.6 d MJD Modified Julian Date of measurement
23- 33 F11.3 e- Flux Instrumental CoRoT flux
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Byte-by-byte Description of file (#): mir/*
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Bytes Format Units Label Explanations
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4- 15 F12.6 d MJD Modified Julian Date of measurement
28- 33 F6.3 mJy Flux IRAC flux in the 3.6um or 4.5um band
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Byte-by-byte Description of file (#): xbl/*
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Bytes Format Units Label Explanations
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4- 15 F12.6 d MJDb MJD of beginning of block
19- 30 F12.6 d MJDe MJD of end of block
41- 48 F8.5 ph/s/cm2 Flux ACIS-I flux in the 0.5-8.0keV band
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Byte-by-byte Description of file (#): xbi/*
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Bytes Format Units Label Explanations
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4- 15 F12.6 d MJD Modified Julian Date of measurement
26- 33 F8.5 ph/s/cm2 Flux ACIS-I flux in the 0.5-8.0keV band
45- 51 F7.5 ph/s/cm2 e_Flux rms uncertainty on Flux
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Acknowledgements:
Ettore Flaccomio, ettore.flaccomio(at)inaf.it
(End) Patricia Vannier [CDS] 07-Sep-2018