HCalSG#2-A6 action item: To provide M. Cohen, L. Decin, and the HCalSG with information about the number and locations of stars that the instrument teams will need for calibration. Considering the flux densities of calibration stars (<= 10Jy from 90 micron onwards), we believe that these sources will be useful calibrators for the photometry mode of PACS. Any full wavelength range scan to determine the RSRF will take far too long time to be observed even at a moderate S/N ratio. Possibly, some key wavelengths could be observed with the spectrometer, but only for the brightest stars (few Jy). For the photometry mode, sources should have at least 100 mJy at the filter's central wavelength (70, 110 and 170 micron) to reach a 2% accuracy in less than 20 minutes per filter (but you always get the red channel together with one of the 2 blue filters). => PACS requirements: * 10-15 stars in the following flux density range: Brightest stars: few Jy (where they overlap the flux range of the asteroids) down to about 100 mJy. Additionally we would need a half dozen stars available during PV, preferably covering the whole flux range few Jy - 100mJy. * at least 1 object available at any time. Likely there will be a high visibility region to which we can return regularly (gamma dra, delta dra, as was the case with ISO) * It should be checked that the sources do not suffer from cirrus confusion noise (can be checked by applying the Helou & Beichman cirrus confusion formula (see also Kiss et al. AA 379,116 (2001)) * wavelength range for the models: up to 250 micron * best possible flux accuracy (<10% at far-IR) * units: flux density [Jy] over wavelength [micrometer] * spacing in wavelength: similar to earlier models for ISO (typical interpolation methods should not produce any degradation of model quality): about 30 datapoints over the PACS wavelength range * format: - list of flux densities at the central wavelengths of the 3 filters. - final models in FITS format, including model parameters in FITS header * stellar models and input parameters should be well documented Additional info: From the ISOPHT standards stars list the following stars meet the criteria given above. 1) HR 617 (alp Ari) f_90 = 1028mJy f_180 = 253mJy 2) HR 5340 (alp Boo) f_90 = 9300mJy f_180 = 2286mJy 3) HR 3748 (alp Hya) f_90 = 1730mJy f_180 = 427mJy 4) HR 1457 (alp Tau) f_90 = 8461mJy f_180 = 2082mJy 5) HR 337 (bet And) f_90 = 3526mJy f_180 = 868mJy 6) HR 2990 (bet Gem) f_90 = 1474mJy f_180 = 358mJy 7) HR 8775 (bet Peg) f_90 = 4957mJy f_180 = 1218mJy 8) HR 1654 (eps Lep) f_90 = 713mJy f_180 = 175mJy 9) HR 4763 (gam Cru) f_90 = 11920mJy f_180 = 2930mJy 10) HR 6705 (gam Dra) f_90 = 2012mJy f_180 = 495mJy 11) HR 7310 (del Dra) f_90 = 257mJy f_180 = 63mJy 12) HR 7980 (ome Cap) f_90 = 517mJy f_180 = 127mJy 13) HR 2131 f_90 = 118mJy f_180 = (29mJy) 14) HR 5826 (the UMi) f_90 = 173mJy f_180 = (42mJy) coordinates (2000) Sp type 1) HR 617 02 07 10.4071 +23 27 44.723 K2III * 2) HR 5340 14 15 39.6720 +19 10 56.677 K1.5III * 3) HR 3748 09 27 35.2433 -08 39 30.969 K3II-III * 4) HR 1457 04 35 55.2387 +16 30 33.485 K5III * 5) HR 337 01 09 43.9236 +35 37 14.008 M0III * 6) HR 2990 07 45 18.9503 +28 01 34.315 K0IIIb 7) HR 8775 23 03 46.4575 +28 04 58.041 M2.5II-III * 8) HR 1654 05 05 27.6643 -22 22 15.717 K4III * 9) HR 4763 12 31 09.9593 -57 06 47.562 M3.5III 10) HR 6705 17 56 36.3699 +51 29 20.022 K5III * 11) HR 7310 19 12 33.3000 +67 39 41.549 G9III 12) HR 7980 20 51 49.2910 -26 55 08.877 M0III * 13) HR 2131 06 01 16.2979 -33 54 42.608 K5III 14) HR 5826 15 31 24.9293 +77 20 57.667) K5III * observed by ISOPHOT in minimap mode Couple of stars observed by ISOPHOT in minimap mode with f_pred@180um > 0.1 Jy and not in the above list HD HR coordinate (2000) Sp type --------------------------------------------------- 48915 2491 06 45 08.92 -16 42 58.0 A1V (Sirius) 187642 7557 19 50 47.00 +08 52 06.0 A7V -- --- Joris Blommaert --- Instituut voor Sterrenkunde, K.U.Leuven --- Celestijnenlaan 200 B --- B-3001 Leuven, Belgium --- Tel: +32-16-32.79.16 Fax: +32-16-32.79.99 --- Joris.Blommaert@ster.kuleuven.ac.be http://www.ster.kuleuven.ac.be/