1 / 16

OH observations with ALFA

This study presents a detailed analysis of observations conducted using the ALFA and L-wide systems on July 30, 2003, focusing on the OH line flux of comet K4 LINEAR. We examine scaling factors and signal-to-noise ratios (SEFD) for various line configurations. The sensitivity of ALFA is assessed to be approximately 75% that of L-wide at the OH line center and 55% in off-pixels. Our findings highlight the significant advantage of simultaneous observations for rapidly changing celestial phenomena, suggesting improvements in detection capabilities for extended sources.

melodie-carpenter
Télécharger la présentation

OH observations with ALFA

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. OH observations with ALFA

  2. OH hexmap with L-wideComet 2003 K4 LINEAR July 30

  3. Direct comparison 1667 OH line

  4. Match line flux in 1667 line

  5. Check scaling for 1665 line

  6. 9-level x 1.2 Tsys 25K SEFD 2.2 Jy 3-level (both lines) Tsys ? >30K SEFD effective 3.7 Jy Spider scans find SEFD=4.3,5.7 PolB has some problem that can probably be improved L-wide/ALFA = 2.4 line flux ratio

  7. SEFD Pol A

  8. SEFD Pol B

  9. Spider scans central pixel

  10. Spider scans pixel 2

  11. OH hexmap with L-wide

  12. Check pixels 1-6 with L-wide map • SEFD for off pixels is ~1.33 central value (based on measurements at 1400 MHz) • Spacing is 4.1 arcmin in L-wide map, 5 arcmin for ALFA • Assume no contamination from center for now

  13. Compare off pixels 2 and 5

  14. Conclusions • ALFA sensitivity is ~75% that of L-wide at OH in center, ~55% in off pixels • For extended sources, sensitivity and coverage tradeoff is factor of 2–3 net improvement over L-wide (compared to a factor of ~5 at HI) • The simultaneity is a big plus for comets which change on timescales of hours

  15. Compare off pixels 3 and 6

  16. Compare off pixels 1 and 4

More Related