J/ApJS/271/3 TMRT Ka-band (26.1-35GHz) obs. of Orion-KL (Liu+, 2024)
The first Ka-band (26.1-35GHz) blind line survey toward Orion KL.
Liu X., Liu T., Shen Z., Qin S.-L., Luo Q., Gong Y., Cheng Yu, Henkel C.,
Gu Q., Zhu F., Zhang T., Zhao R., Wu Y., Li B., Li J., Zhao Z., Wang J.,
Zhong W., Liu Q., Xia Bo, Fu Li, Yan Z., Zhang C., Wang L., Ye Q.,
Yang A., Xu F., Zhang C., Dutta S., Li S., Liu M., Yang D., Li C.,
Chen Li
<Astrophys. J. Suppl. Ser., 271, 3 (2024)>
=2024ApJS..271....3L 2024ApJS..271....3L
ADC_Keywords: Star Forming Region; Radio lines; Molecular data; Spectra, radio
Keywords: Single-dish antennas ; Millimeter astronomy ; Radio spectroscopy ;
Star formation ; Young stellar objects ; OB stars ;
Molecular clouds ; Interstellar line emission ;
Interstellar molecules ; Recombination
Abstract:
We conducted a Ka-band (26.1-35GHz) line survey toward Orion KL using
the TianMa 65m Radio Telescope (TMRT). It is the first blind line
survey in the Ka band and achieves a sensitivity at the mK level
(1-3mK at a spectral resolution of ∼1km/s). In total, 592 Gaussian
features are extracted. Among them, 257 radio recombination lines
(RRLs) are identified. The maximum Δn of RRLs of H, He, and C
are 20, 15, and 5, respectively. Through stacking, we have detected
the β lines of ion RRLs (RRLs of C+ with the possible
contribution of other ions like O+) for the first time, and a
tentative signal of the γ lines of ion RRLs can also be seen on
the stacked spectrum. Besides this, 318 other line features were
assigned to 37 molecular species, and 10 of these species were not
detected in the Q-band survey of TMRT. The vibrationally excited
states of nine species were also detected. The emission of most
species can be modeled under LTE. A number of transitions of E-CH3OH
(J2-J1) display maser effects, which are confirmed by our
modeling, and besides the bumping peak at J∼6, there is another peak
at J∼13. Methylcyanoacetylene (CH3C3N) is detected in Orion KL for the
first time. This work emphasizes that the Ka band, which was long
ignored for spectral line surveys, is very useful for surveying RRLs
and molecular lines simultaneously.
Description:
The observations were carried out using the TianMa 65m Radio Telescope
(TMRT), built and operated by the Shanghai Astronomical Observatory.
The TMRT is located in the western suburbs of Shanghai, China.
This Ka-band line survey of Orion KL covered 26.1-35GHz.
The observations were conducted from 2022-Sep-28 to 2022-Oct-30. The
targeting position is RAJ2000=05:35:14.55,DEJ2000=-05:22:31.0.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
05 35 14.16 -05 22 21.4 Orion KL = NAME Orion-KL
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table6.dat 119 335 Identification and Gaussian fitting
of molecular lines
table7.dat 77 278 Identification and Gaussian fitting
of radio recombination lines (RRLs)
orionkltmrtka_spec.fits 2880 137 Spectrum of Orion KL observed with
the TMRT in the Ka-band (26.1-35GHz)
in FITS format (Data behind Figure1)
orionklmodeledkaspecall.fits 2880 137 Model spectrum of Orion KL in the
Ka-band in FITS format
(Data behind Figure 3)
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See also:
J/ApJ/428/693 : Rosette Nebula & Maddalena Cloud structures (Williams+ 1994)
J/A+A/327/1177 : Kinematics & electron temperatures in Orion A (Wilson+ 1997)
J/ApJ/768/81 : Ethyl cyanide, CH3CH2CN, vibrational states (Daly+, 2013)
J/A+A/564/A68 : Orion A GMC 13CO and C18O maps (Shimajiri+, 2014)
J/MNRAS/452/3969 : ATCA Survey of Sagittarius B2 at 7mm (Corby+, 2015)
J/A+A/581/A48 : 1.3cm line survey toward Orion KL (Gong+, 2015)
J/A+A/604/A32 : Orion BN-KL ALMA view (Pagani+, 2017)
J/A+A/605/A76 : Spectrum of Orion KL between 41.5 and 50GHz (Rizzo+, 2017)
J/A+A/647/A42 : Detected CH2 spectra (Jacob+, 2021)
J/ApJS/263/13 : 34.8-50GHz obs. toward Orion KL (Liu+, 2022)
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 F8.2 MHz Freq [26120.5/34999.6]? Observed frequency (1)
10- 24 A15 --- Species Molecular species (2)
26- 34 F9.3 MHz RFreq [26120.5/34999.7]? Rest frequency
36- 62 A27 --- Transition ? Molecular transition JKa,Kc (3)
64- 69 F6.1 K Eu [1.4/2090.5]? Upper-level energy
71- 76 F6.4 10-6/s Aij [0.0006/4.5]? Einstein coefficient
78- 84 F7.4 K.km/s I [0.007/69.7]? Integrated intensity using
main-beam temperature
86- 91 F6.4 K.km/s e_I [0.0002/0.1]? Uncertainty in I
93- 96 F4.1 km/s DV [0.9/76]? Line width
98- 100 F3.1 km/s e_DV [0.1/8]? Uncertainty in DV
102- 109 E8.2 K Tmb-pk [0.0012/14.1]? Peak main-beam temperature
111- 115 F5.1 km/s VLSR [-23.6/33.5]? Local standard of rest
velocity
117- 119 F3.1 km/s e_VLSR [0.1/6]? Uncertainty in VLSR
--------------------------------------------------------------------------------
Note (1): Doppler correction has been applied assuming LSR source velocity of
6km/s. Empty rows correspond to molecular lines blended with RRLs.
Note (2): Emitter of ion RRL is denoted as XII and f-rest is adopted as rest
frequency of corresponding CII RRL. Unidentified species denoted as U.
Note (3): Rows with same species name and transition label correspond to
different emission components of same transition. Transition labels
for HCN vt=1 are Jp with parity p. Transition labels for CH3OCH3
are JsK with symmetry substate s. Transition labels are (J,K)
for NH3 convention lines.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 F8.2 MHz Freq [26162.5/34955.6]? Observed frequency (1)
10 A1 --- f_Freq [*] * = only marginally detected
12- 25 A14 --- Species Radio recombination line (2)
27- 35 F9.3 MHz RFreq [26161.6/34954.4] Rest frequency
37- 42 F6.3 K.km/s I [0.009/61.4]? Integrated intensity using
main-beam temperature
44- 48 F5.3 K.km/s e_I [0.001/0.2]? Uncertainty in I
50- 53 F4.1 km/s DV [2.2/45]? Line width
55- 58 F4.1 km/s e_DV [0.1/10]? Uncertainty in DV
60- 67 E8.2 K Tmb-pk [0.0016/2.4]? Peak main-beam temperature
69- 73 F5.1 km/s VLSR [-16/21.2] Local standard of rest velocity
75- 77 F3.1 km/s e_VLSR [0.1/4] Uncertainty in VLSR
--------------------------------------------------------------------------------
Note (1): Doppler correction has been applied assuming LSR source velocity of
6km/s.
Note (2): Emitter of ion RRL is denoted as XII and f-rest is adopted as rest
frequency of corresponding CII RRL. RRLs blended with molecular
lines are not included.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 22-Apr-2024