MSST campaign on PG1605 072: 4m spectroscopy

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MSST campaign on PG16050724m spectroscopy

• C.S.Jeffery, U.Heber, S.OToole, S.Dreizler,
  S.Schuh, V.Woolf. S.Falter, A.Nitta, M.Billères

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Observations

• Aim observe PG1605072 in radial velocity to
  resolve measure amplitudes of many modes.
• MSST 4m 1 week at high resolution
• MSST 2m several weeks at moderate resolution
  (OToole et al. 2005)
• MSST phot WET community volunteered photometry
  over several weeks (Schuh et al. 2003,)

• Trailed Long-Slit Spectroscopy at 1A resolution
• Apache Point Observatory 3.5m (H? Nitta)
• Calar Alto 3.6m TWIN (H? blue Falter)
• ESO 3.6m (blueraincloudsmoon Billeres)
• Drift-mode spectroscopy
• AAT (UK PATT)
• WHT 4.2m (UK PATT)
• All data reduced in same way velocities

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Red and blue velocity amplitudes
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Modelling NRP spectra

• STERNE LTE lineblanketed model atmospheres
• Teff, log g, Xi
• sdB model grid Teff25000-35000K, log4.0-6.0
• SPECTRUM spectrum synthesis with specific
  intensities I??
• model, Xi, vturb, lt?gt, lt?gt
• sdB grid ? 0,...1, ?3800 - 7000 Å
• BRUCE surface velocity vectors at 25000
  positions
• Teff, M, Req, i, vrot, ltl,m,P,vgt, nt, tn
• KYLIE apparent fluxes, F?t
• lt?gt, R
• FAST Fourier analysis of spectroscopic time
  series
• ---- Photometry simulation (Ramachandran et al
  2004)
• ---- Line profile studies whatever you want to
  do !

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l0,m0
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l0,m0
l2,m0
l2,m2
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Comparative amplitudes What you measure depends
on wavelength and resolution

• Velocity amplitudes measured from theoretical
  spectra with f2.07 mHz, vpuls10 km/s, resampled
  at the temporal and spectral resolution of the
  MSST 4m observations and then analysed as
  time-series spectroscopy.
• Selected largest amplitude mode for each degree
  at the given inclination.

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Rotation

• Heber et al (1999) v sini 39 km/s texp600s
  ?
• Kawaler (1999) veq130 km/s wide triplet ?
• Pereira Lopes(2005) 2 uHz splitting 4-5d
  rotation ?
• How is this related to modulation of the 2.076
  mHz peak?

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l0,m0
l2,m0
l2,m2
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Conclusions

• amplitude of principle peak at 2.076 mHz
• high during most of MSST 2m campaign
• low during 2n of Calar Alto observations
• red/blue ratios consistent with low-degree modes
• vsini obtained from Keck may substantially
  overestimate true value - PG1605 not necessarily
  a rapid rotator
• evidence of beating between closely spaced modes?
• evidence for rotationally split m-values?