HERCULES CLUSTER 21-cm LINE SURVEY

Here are some preliminary results from a VLA survey of four beam areas in the Hercules Cluster. Grey scale is from the POSS, contours are from the 21-cm cubes (0th moment maps, computed with both XMOM and XGAUS and results matched for consistency). Note how little correlation there is between the optical and HI luminosities.

northeast field (detail)

Click above to see a small region of the center VLA field, with contours at about the 5 sigma level in the HI, and a grey scale of the POSS.

center field (detail)

Click on the box to see a small region of the northeast VLA field, with contours at about the 5 sigma level in the HI, and a grey scale of the POSS.

Here are some spectra from galaxies detected above a threshold of 3x10**8 solar masses :

• spectra of galaxies in the northeast field
• spectra of more galaxies in the northeast field
• spectra of galaxies in the center field
• spectra of more galaxies in the center field
• spectra of galaxies in the southwest field
• spectra of galaxies in the A2147 field

  The scales and notations of these spectra are not very legible, sorry. In all cases the velocity (cz) runs from 9300 km/s to 12500 km/s left to right. The vertical scale changes, but it is typically -0.5 mJy to + a few mJy. These spectra are integrated over an area defined by a threshold on moment 0 (XMOM) or "flux" (XGAUS). The beam area is divided out, so the units are real mJy. The pixel coordinates of the peak pixel are also illegible (at the upper center of each spectrum), mail me if you want to know specific galaxy coordinates, etc.

  Now, to see grey scale representations of the XMOM 0th moment maps of the northeast and center fields, click below. The pixel size is 6", the resolution about 25", and the greyscale is -100 to +250 mJy km/s.

  • greyscale of the northeast field
  • greyscale of the center field

  Here are contour diagrams of the HI column density (integrated over velocity) superposed on POSS images of all the galaxies detected in the Northeast field : NE030, NE089, NE112, NE142, NE166, NE169, NE176, NE178, NE187, NE204, NE208, NE222, NE228, NE240, NE246, NE250, NE264, NE300, NE320, NE350, NE392, NE398,

  and the same for the Center field : CE018, CE042, CE048, CE050, CE060, CE061, CE070, CE086, CE095, CE102, CE109, CE122, CE137, CE143, CE150, CE155, CE159, CE160, CE166, CE176, CE189, CE194, CE199, CE200, CE224, CE244, CE253, CE294.

  and the same for the SW field : SW048, SW054, SW083, SW089, SW103, SW146, SW159, SW174, SW194, SW222.

  and the same for the 47 field : 47030, 47035, 47052, 47097, 47138, 47154, 47166, 47193, 47211, 47295, 47307.

  And the corresponding channel-maps, with velocity indicated in the upper right corners :

  example :

  A2151 NorthEast field : ne030, ne089, ne112, ne142, ne166, ne169, ne176, ne178, ne187, ne204, ne208, ne222, ne228, ne240, ne246, ne250, ne264, ne300, ne320, ne350, ne392, ne398.

  A2151 Center field : ce018, ce042, ce048, ce050, ce060, ce061, ce070, ce086, ce095, ce102, ce109, ce137, ce143, ce150, ce155, ce166, ce176, ce189, ce194, ce199, ce200, ce224, ce244, ce253, ce294.

  A2151 SouthWest field : sw048, sw054, sw083, sw089, sw103, sw146, sw159, sw174, sw194, sw222.

  A2147 field : 47030, 47052, 47097, 47138, 47154, 47166, 47211.

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  This page written by John Dickey, john@ast1.spa.umn.edu