J/AJ/168/10 Star Formation Activities in W51A (Zhang+, 2024)
Masers and Star Formation Activities in W51A.
Zhang Y.-K., Chen Xi, Wang Y.-X., Song S.-M., Liu J.-T., Lu Y.
<Astron. J., 168, 10 (2024)>
=2024AJ....168...10Z 2024AJ....168...10Z
ADC_Keywords: H II regions; Star Forming Region; YSOs; Photometry, infrared;
Keywords: Star formation ; Interstellar masers ; Astrophysical masers ;
Young stellar objects ; Protostars
Abstract:
Concurrently with the maser flare observed in W51-North during the 3
month monitoring of H2O, NH3, and CH3OH maser variability from 2020
January to April using the Tianma 65m Radio Telescope, we conducted
Very Large Array mappings for these three maser species across the
entirety of W51A region. After finding the ring-shaped H2O maser which
might trace the disk surrounding the protostar residing in W51-North,
the NH3 (9,6) maser delineated a jet which might be illuminated in the
luminosity outburst possibly caused by the infalling streamer's
interaction with the protostar's disk. An analysis of the
comprehensive distribution of maser spots allowed us to affirm that
W51N4 or ALMAmm31 serves as the primary source of the Lacy jet.
Furthermore, we observed that class I methanol maser spots may extend
beyond the locations of the H2O and NH3 (9,6) masers within the
outflow. Additionally, emissions from other NH3 maser transitions
coincided with specific 1.3mm continuum sources. The arrangement of
H2O maser spots in the vicinity of W51e2-E potentially indicates
episodic accretions in this source. Combining the data from the
Atacama Large Millimeter/submillimeter Array data archive for
W51-North, W51e2, and W51e8, we have discovered that the H2O, NH3, and
CH3OH masers, as well as the HC3N and SiO emissions are found to be
good tools for tracing outflow in this work for W51A.
Description:
the K-band (18-26.5GHz) VLA observation toward W51-IRS2 (J2000
position: R.A.=19h23m40.047", decl.=14deg31'05.530" ) was carried out
on 2020 March 31, with the C-array configuration and the field of view
expanding to include the W51e2/e8 region.
Objects:
-----------------------------------------
RA (2000) DE Designation(s)
-----------------------------------------
19 23 29.29 +14 31 37.9 W51A = W 51a
-----------------------------------------
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 78 3649 Details of the detected H2O maser spots
table3.dat 74 387 Parameters of the detected NH3 (9,6) maser spots
table4.dat 76 62 Parameters of the detected CH3OH maser spots
table5.dat 78 147 Parameters of the rest of the detected NH3 maser
spots
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See also:
J/MNRAS/301/640 : Ultracompact H II regions studies. II. (Walsh+, 1998)
J/MNRAS/359/1498 : Class I and class II methanol masers (Ellingsen+, 2005)
J/ApJ/720/1055 : VBLA observations of W51 Main/South (Sato+, 2010)
J/ApJS/196/9 : 95GHz methanol maser survey toward GLIMPSE EGO (Chen+, 2011)
J/ApJS/206/9 : New EGOs from Spitzer GLIMPSE II survey. I. (Chen+, 2013)
J/MNRAS/444/566 : Methanol maser associated outflows (de Villiers+, 2014)
J/MNRAS/439/2584 : Southern methanol masers at 36 and 44GHz (Voronkov+, 2014)
J/A+A/595/A27 : JVLA images of W51A (Ginsburg+, 2016)
J/A+A/589/A44 : W51 Main NH3 and CH3OH data cubes (Goddi+, 2016)
J/ApJ/854/170 : Methanol (CH3OH) and OH masers in NGC 6334I (Hunter+, 2018)
J/MNRAS/505/2801 : ATOMS Paper III, massive star-forming regions (Liu+, 2021)
J/ApJS/263/9 : Multiple maser transitions G358.93-0.03 burst (Miao+, 2022)
J/A+A/657/A30 : W51 North ALMA 1.3 and 3mm images (Tang+, 2022)
J/A+A/663/A177 : High-mass star-forming regions cyanopolyyne (Wang+, 2022)
J/ApJS/260/34 : NH3 transitions detections toward W51 IRS2 (Zhang+, 2022)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- Name Source name
17- 23 F7.3 arcsec RRA [-91/150] Relative Right Ascension (J2000) (1)
25- 29 F5.3 arcsec e_RRA [0.001/0.5] Uncertainty in RRA (J2000) (1)
31- 38 F8.3 arcsec RDE [-151/72] Relative Declination (J2000) (1)
40- 44 F5.3 arcsec e_RDE [0.001/0.4] Uncertainty in RDE (J2000) (1)
46- 51 F6.2 km/s vel [-39.32/147] Velocity of maser spot
53- 59 F7.2 Jy/beam pFlux [0.02/4233] Peak flux density from 2D Gaussian
fit of maser spot
61- 64 F4.2 Jy/beam e_pFlux [0/7] Uncertainty in pFlux
66- 72 F7.2 Jy iFlux [0.01/4447] Total flux density from 2D Gaussian
fit of maser spot
74- 78 F5.2 Jy e_iFlux [0/14] Uncertainty in iFlux
--------------------------------------------------------------------------------
Note (1): Positions are relative to the center of the VLA view field: W51-North
(J2000 position: RA = 19h 23m 40.047s, Dec = 14deg 31' 5.530").
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- Name Source name
17- 22 F6.3 arcsec RRA [-7/58] Relative Right Ascension (J2000) (1)
24- 28 F5.3 arcsec e_RRA [0.003/0.2] Uncertainty in RRA (J2000) (1)
30- 36 F7.3 arcsec RDE [-39/49] Relative Declination (J2000) (1)
38- 42 F5.3 arcsec e_RDE [0.003/0.9] Uncertainty in RDE (J2000) (1)
44- 48 F5.2 km/s vel [49.92/67.5] Velocity of maser spot
50- 55 F6.3 Jy/beam pFlux [0.01/11.9] Peak flux density from 2D Gaussian
fit of maser spot
57- 61 F5.3 Jy/beam e_pFlux [0.003/0.05] Uncertainty in pFlux
63- 68 F6.3 Jy iFlux [0.01/11.6] Total flux density from 2D Gaussian
fit of maser spot
70- 74 F5.3 Jy e_iFlux [0.005/0.2] Uncertainty in iFlux
--------------------------------------------------------------------------------
Note (1): Positions are relative to the center of the VLA view field: W51-North
(J2000 position: RA = 19h 23m 40.047s, Dec = 14deg 31' 5.530").
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- Name Source name
11- 19 A9 --- Tr Methanol transitions
21- 26 F6.3 arcsec RRA [-1/59] Relative Right Ascension (J2000) (1)
28- 32 F5.3 arcsec e_RRA [0.001/0.2] Uncertainty in RRA (J2000) (1)
34- 40 F7.3 arcsec RDE [-30/29] Relative Declination (J2000) (1)
42- 46 F5.3 arcsec e_RDE [0.001/0.2] Uncertainty in RDE (J2000) (1)
48- 52 F5.2 km/s vel [57.7/63.9] Velocity of maser spot
54- 58 F5.3 Jy/beam pFlux [0.01/2.25] Peak flux density from 2D Gaussian
fit of maser spot
60- 64 F5.3 Jy/beam e_pFlux [0.003/0.005] Uncertainty in pFlux
66- 70 F5.3 Jy iFlux [0.02/2.28] Total flux density from 2D Gaussian
fit of maser spot
72- 76 F5.3 Jy e_iFlux [0.004/0.02] Uncertainty in iFlux
--------------------------------------------------------------------------------
Note (1): Positions are relative to the center of the VLA view field: W51-North
(J2000 position: RA = 19h 23m 40.047s, Dec = 14deg 31' 5.530").
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- Name Source name
17- 21 A5 --- Tr Ammonia maser transition
23- 28 F6.3 arcsec RRA [-6/17] Relative Right Ascension (J2000) (1)
30- 34 F5.3 arcsec e_RRA [0.001/0.4] Uncertainty in RRA (J2000) (1)
36- 42 F7.3 arcsec RDE [-47/7] Relative Declination (J2000) (1)
44- 48 F5.3 arcsec e_RDE [0.001/0.4] Uncertainty in RDE (J2000) (1)
50- 54 F5.2 km/s vel [44.93/56.28] Velocity of maser spot
56- 60 F5.3 Jy/beam pFlux [0.01/3.11] Peak flux density from 2D Gaussian
fit of maser spot
62- 66 F5.3 Jy/beam e_pFlux [0.002/0.006] Uncertainty in pFlux
68- 72 F5.3 Jy iFlux [0.01/3.11] Total flux density from 2D Gaussian
fit of maser spot
74- 78 F5.3 Jy e_iFlux [0.004/0.02] Uncertainty in iFlux
--------------------------------------------------------------------------------
Note (1): Positions are relative to the center of the VLA view field: W51-North
(J2000 position: RA = 19h 23m 40.047s, Dec = 14deg 31' 5.530").
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 09-Aug-2024