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Observations of Extragalactic Neutral Hydrogen

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Observations of Extragalactic. Neutral Hydrogen. Spencer Wolfe. Kristina Nyland. Laura Trouille ... provides distance to galaxy (if unknown) Width of line ... – PowerPoint PPT presentation

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Title: Observations of Extragalactic Neutral Hydrogen


1
Observations of Extragalactic Neutral Hydrogen
  • Spencer Wolfe
  • Kristina Nyland
  • Laura Trouille
  • Blakesley Burkhart
  • Robert Minchin

2
Why observe the 21 cm line in other galaxies?
  • Center of line
  • provides recessional velocity of galaxy
  • provides distance to galaxy (if unknown)
  • Width of line
  • provides rotational velocity of the galaxy
  • provides dynamical mass of the galaxy
  • Total flux in HI line
  • provides HI mass of the galaxy
  • probes correlations with optical galaxy
    morphology, dynamical mass, IR flux, and
    variations with redshift

Above The Circinus spiral galaxy mapped in HI by
the ATCA. The left and right sides represent
(respectively) the moment 0 (integrated flux) and
the moment 1 (velocity).
3
Instrument Set-up
  • L-band receiver (centered at 1420.406 MHz)
  • Filter at 1370-1470 MHz
  • Backend WAPP correlator (25-50 MHz)
  • Standard on/off observing mode
  • 8 galaxies observed in 2 hours
  • all galaxies chosen w/ velocities lt 10,000 km/s
  • 300 sec integration time per target

4
Lets Play Guess the Profile
NGC 6021
NGC 5996
Spiral (SBc, starburst)
Elliptical
First 21-cm detection of NGC 6021 !
5
UGC 10281, SB(s)m, z0.03
M(HI) 3.8e8 Mdyn 2.3e10
6
CGCG 082-035
M(HI) 1.4e9 Mdyn 7.5e9
Unknown classification in NED, found in 2MASS
survey
M(HI) 9.7e8 Mdyn 4.5e9
UGC 10805
SBm
7
M(HI) 1.4e9 Mdyn 4.7e10
UGC 10841
Sdm
M(HI) 3.6e8 Mdyn 8.5e10
IC 1135
Sa
i30 deg
8
Mass Ratios
Target Name Morphology Mdyn/M(HI)
UGC 10805 Sbm 4.56
CGCG082-035 unknown 5.2
NGC 5996 Sbc stbur 16.3
UGC 10841 Sdm 23.9
UGC 10281 SB(s)m 59.8
IC 1135 Sa 233
NGC 6021 E 1390
1) HI in looser spirals tends to account for a
greater portion of their total mass. 2) Tighter
spiral and elliptical have a lower fraction of HI
compared to their total mass. 3) This supports
the general view of spiral vs elliptical galaxy
characteristics.
9
Acknowledgements
We would like to thank Robert Minchin for his
help with observing and reducing our data.
Thanks Robert!
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