{
  "createdOn": 1013445464000,
  "submitter": "Don Lamb at U.Chicago  <lamb@oddjob.uchicago.edu>",
  "version": 2,
  "bibcode": "2002GCN..1247....1L",
  "circularId": 1247,
  "subject": "SN2002ap (SN/GRB?) optical spectrographic observations",
  "editedOn": 1777052502503,
  "body": "J. T. Lauroesch, D. G. York, C. Hastings, D. V. Bowen, D. Meyer, and\nD. Q. Lamb report:\n\nWe obtained 75 minutes of integration (five 15-minute exposures) on\nSN2002ap using the echelle spectrograph (ARCES) on the Apache Point\nObservatory 3.5-meter telescope.  The spectra were taken with a 1.6\narcsecond wide slit, 3.2 arcsec long, in seeing of about 1.5 arcsec.\nThe spectra give complete spectral coverage from 3600 A to 10500A. The\nsignal to noise ratio (per pixel) is about 20 at Ca II and 50 at Na I.\n\nThese spectra, at a resolution of 8 km/s, show clear detections of\ninterstellar NaI and CaII in both the Milky Way and M74.  A  weak,\nnarrow, NaI feature (D1 and D2) is detected in M74 with a column\ndensity of approximately 2.5e11, suggesting there may be little cold\ninterstellar gas in M74 in front of the SN.  Assuming the \"typical\"\nGalactic relation between NaI and HI, this fact would suggest a total\nhydrogen column of approximately 5e19 in M74 along this sightline.  Two\ncomponents are seen in M74 in CaII; one narrow, corresponding in\nvelocity to the NaI absorption noted above, and a second broader\ncomponent, approximately +25 km/sec with respect to the Na I feature.\nThe Ca II features each span roughly 50 km/sec, and are centered near\n650 km/sec (heliocentric).  The Galactic Na I and Ca II lines are about\n5 times stronger that their M74 counterparts in the SN spectrum.  This\nobject, while it is still bright, is ideal for measuring interstellar\nabundances in the outer part of the M74 galaxy.\n\nThis sightline passes near the location of a known Galactic high\nvelocity H I cloud (Wakker 2001) at approximately -100 km/sec (LSR);\nhowever, no absorption is detected at these velocities in either Ca II\nor Na I to limits of 20 and 10 milli-Angstroms respectively.\n\nNo other significant narrow absorption or emission lines were seen in\nthe spectrum.\n\nFurther observations are in progress.",
  "eventId": "SN 2002ap",
  "email": "lamb@oddjob.uchicago.edu",
  "editedBy": "Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov>"
}