A Search For Interstellar Urea With CARMA Hsin-Lun Kuo, Lewis Snyder, Douglas Friedel, Leslie...
Transcript of A Search For Interstellar Urea With CARMA Hsin-Lun Kuo, Lewis Snyder, Douglas Friedel, Leslie...
![Page 1: A Search For Interstellar Urea With CARMA Hsin-Lun Kuo, Lewis Snyder, Douglas Friedel, Leslie Looney, Benjamin McCall (UIUC), Anthony Remijan (NRAO), Frank.](https://reader036.fdocuments.in/reader036/viewer/2022070305/5515649755034685568b5c64/html5/thumbnails/1.jpg)
A Search For Interstellar Urea
With CARMA
Hsin-Lun Kuo, Lewis Snyder, Douglas Friedel, Leslie Looney,
Benjamin McCall (UIUC),
Anthony Remijan (NRAO), Frank Lovas (NIST), Jan Hollis
(NASA)
![Page 2: A Search For Interstellar Urea With CARMA Hsin-Lun Kuo, Lewis Snyder, Douglas Friedel, Leslie Looney, Benjamin McCall (UIUC), Anthony Remijan (NRAO), Frank.](https://reader036.fdocuments.in/reader036/viewer/2022070305/5515649755034685568b5c64/html5/thumbnails/2.jpg)
Motivation
Urea (NH2)2CO has measured and calculated laboratory frequencies good to a few kHz.
In preparation of CARMA search for protonated methanol (frequencies measured by McCall group), we wish to develop procedures with trustworthy calibrator fluxes, proper baseline subtraction, and self calibration to extract weak emission lines from CARMA data.
![Page 3: A Search For Interstellar Urea With CARMA Hsin-Lun Kuo, Lewis Snyder, Douglas Friedel, Leslie Looney, Benjamin McCall (UIUC), Anthony Remijan (NRAO), Frank.](https://reader036.fdocuments.in/reader036/viewer/2022070305/5515649755034685568b5c64/html5/thumbnails/3.jpg)
CARMA (Combined Array for Research in Millimeter-wave Astronomy)
Owens Valley Radio Observatory (OVRO) -- 10.4 m X6
Berkeley-Illinois-Maryland Association (BIMA) -- 6.1 m X9 105 baselines Angular resolution about 0.3", 0.8", 2", 5", or 10" at 100
GHz in A, B, C, D, and E configuration Operates at 3 mm (85-116 GHz) and 1 mm (215-270
GHz)
![Page 4: A Search For Interstellar Urea With CARMA Hsin-Lun Kuo, Lewis Snyder, Douglas Friedel, Leslie Looney, Benjamin McCall (UIUC), Anthony Remijan (NRAO), Frank.](https://reader036.fdocuments.in/reader036/viewer/2022070305/5515649755034685568b5c64/html5/thumbnails/4.jpg)
Urea LinesFrequency(GHz) Q.N. Frequency(GHz) Q.N.
85.082429(7) 4(4,1)-3(3,0) 211.077808(31) 18(*,17)-17(*,16)
91.936572(9) 7(*,6)-6(*,5) 211.177686(45) 19(*,19)-18(*,18)
92.031813(11) 8(*,8)-7(*,7) 221.907450(37) 19(*,18)-18(*,17)
102.767529(10) 8(1,7)-7(2,6) 222.007452(53) 20(*,20)-19(*,19)
102.767550(10) 8(2,7)-7(1,6) 232.736742(44) 20(*,19)-19(*,18)
102.864309(11) 9(*,9)-8(*,8) 232.836861(63) 21(*,21)-20(*,20)
108.265140(9) 5(5,1)-4(4,0) 243.565664(53) 21(*,20)-20(*,19)
112.023887(9) 5(5,0)-4(4,1) 243.665896(74) 22(*,22)-21(*,21)
254.394200(62) 22(*,21)-21(*,20)
254.494539(86) 23(*,23)-22(*,22)
265.222330(73) 23(*,22)-22(*,21)
265.322772(99) 24(*,24)-23(*,23)
![Page 5: A Search For Interstellar Urea With CARMA Hsin-Lun Kuo, Lewis Snyder, Douglas Friedel, Leslie Looney, Benjamin McCall (UIUC), Anthony Remijan (NRAO), Frank.](https://reader036.fdocuments.in/reader036/viewer/2022070305/5515649755034685568b5c64/html5/thumbnails/5.jpg)
Urea Energy Levels
![Page 6: A Search For Interstellar Urea With CARMA Hsin-Lun Kuo, Lewis Snyder, Douglas Friedel, Leslie Looney, Benjamin McCall (UIUC), Anthony Remijan (NRAO), Frank.](https://reader036.fdocuments.in/reader036/viewer/2022070305/5515649755034685568b5c64/html5/thumbnails/6.jpg)
Continuum Map of Sgr B2 (N)
![Page 7: A Search For Interstellar Urea With CARMA Hsin-Lun Kuo, Lewis Snyder, Douglas Friedel, Leslie Looney, Benjamin McCall (UIUC), Anthony Remijan (NRAO), Frank.](https://reader036.fdocuments.in/reader036/viewer/2022070305/5515649755034685568b5c64/html5/thumbnails/7.jpg)
Urea 1mm Spectra
![Page 8: A Search For Interstellar Urea With CARMA Hsin-Lun Kuo, Lewis Snyder, Douglas Friedel, Leslie Looney, Benjamin McCall (UIUC), Anthony Remijan (NRAO), Frank.](https://reader036.fdocuments.in/reader036/viewer/2022070305/5515649755034685568b5c64/html5/thumbnails/8.jpg)
Line Fits & Spectral Analysis
Beam averaged total number density (cross-correlation array)
(See Appendix in Snyder et al. 2005)
Intensity ratio
€
N tot =Idv∫
Bθa ×θb
QrotSμ 2ν 3
eEu /T × 2.04 ×1020cm−2
€
I1I2
=B1θa1 ×θb1B2θa2 ×θb2
⎛
⎝ ⎜
⎞
⎠ ⎟S1
S2
⎛
⎝ ⎜
⎞
⎠ ⎟ν 1
3
ν 23
⎛
⎝ ⎜
⎞
⎠ ⎟eEu 2 −Eu1
T
![Page 9: A Search For Interstellar Urea With CARMA Hsin-Lun Kuo, Lewis Snyder, Douglas Friedel, Leslie Looney, Benjamin McCall (UIUC), Anthony Remijan (NRAO), Frank.](https://reader036.fdocuments.in/reader036/viewer/2022070305/5515649755034685568b5c64/html5/thumbnails/9.jpg)
Temperature Plots
Plot I1 v.s. Trot
All plots consistent with Trot ~ 80 K
Previous BIMA result Trot = 77 K
€
I1 = I2B1θa1 ×θb1B2θa2 ×θb2
⎛
⎝ ⎜
⎞
⎠ ⎟S1
S2
⎛
⎝ ⎜
⎞
⎠ ⎟ν 1
3
ν 23
⎛
⎝ ⎜
⎞
⎠ ⎟eEu 2 −Eu1
T
![Page 10: A Search For Interstellar Urea With CARMA Hsin-Lun Kuo, Lewis Snyder, Douglas Friedel, Leslie Looney, Benjamin McCall (UIUC), Anthony Remijan (NRAO), Frank.](https://reader036.fdocuments.in/reader036/viewer/2022070305/5515649755034685568b5c64/html5/thumbnails/10.jpg)
Urea 1mm Spectra
![Page 11: A Search For Interstellar Urea With CARMA Hsin-Lun Kuo, Lewis Snyder, Douglas Friedel, Leslie Looney, Benjamin McCall (UIUC), Anthony Remijan (NRAO), Frank.](https://reader036.fdocuments.in/reader036/viewer/2022070305/5515649755034685568b5c64/html5/thumbnails/11.jpg)
Urea 3mm Spectra
![Page 12: A Search For Interstellar Urea With CARMA Hsin-Lun Kuo, Lewis Snyder, Douglas Friedel, Leslie Looney, Benjamin McCall (UIUC), Anthony Remijan (NRAO), Frank.](https://reader036.fdocuments.in/reader036/viewer/2022070305/5515649755034685568b5c64/html5/thumbnails/12.jpg)
Conclusion
Rotational temperature Trot ~ 80K Linewidth ∆v ~ 2.05 km s-1
Beam-averaged total column density Ntot = 9.75 1014 cm-2
Proper coupling of source size to the beam size is essential for flux measurements and detection limits; it helps bring out weak signals that are otherwise blended with extended emission.