Access to Astronomical Catalogues

← Click to display the menu
J/ApJ/581/325       NGC 2071 water masers                    (Seth+, 2002)

Water masers as tracers of protostellar disks and outflows in the intermediate-mass star-forming region NGC 2071. Seth A.C., Greenhill L.J., Holder B.P. <Astrophys. J. 581, 325 (2002)> =2002ApJ...581..325S
ADC_Keywords: H II regions ; Masers ; Radio sources Keywords: H II regions - ISM: individual (NGC 2071) - ISM: jets and outflows - masers - stars: formation Abstract: We have mapped the water maser emission associated with the infrared centers IRS 1 and IRS 3 of the NGC 2071 IR star-forming region at four epochs over ∼4 months with the Very Long Baseline Array. We detected 269 maser features with ∼1km/s line widths and measured 30 proper motions. In each infrared center, the water maser emission appears to trace parts of a protostellar disk and collimated outflow. Description: We observed the 616-523 transition of water (rest frequency 22235.080MHz) toward NGC 2071 IR with the Very Long Baseline Array (VLBA) of the NRAO1 at four epochs in 1996 (see Table 1). A single antenna of the VLA augmented the VLBA, which provided improved sensitivity to emission extended on several milliarcsecond scales. A 16MHz (∼215km/s) recording bandwidth, centered on VLSR=4.66km/s, covered the known velocity range of emission. We processed the data with the VLBA correlator, obtaining 512 spectral channels with a separation of 0.42km/s. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 83 269 Water Maser Features in NGC 2071 IRS1 & IRS3 table3.dat 77 30 Water Maser Proper Motions in NGC 2071 IRS1 & IRS3
See also: J/ApJ/463/205 : CS and NH3 Survey of H2O Maser Emission (Anglada+ 1996) Table 1: Journal of 1996 VLBA Observations -------------------------------------------------------------------------------- Date Track Beam PA rms noise Maser Maser (hr) (mas) (deg) (Jy) spots features -------------------------------------------------------------------------------- Mar 24 8 0.92x 0.51 -9 0.014 337 74 Jun 2 8 1.08x 0.59 -1 0.016 259 67 Jul 5 8 1.03x 0.57 8 0.016 310 81 Aug 3 8.5 1.36x 1.26 24 0.023 168 47 Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 4 A4 --- IRS Object name (IRS1 or IRS3) (G1) 6- 9 A4 --- Maser Maser identification number (1) 11- 15 F5.2 km/s RV Radial velocity 17 A1 --- l_RV Limit flag on RV error 19- 22 F4.2 km/s e_RV Uncertainty in RV (2) 24- 29 F6.3 Jy Speak Peak fitted flux density 31- 35 F5.3 Jy e_Speak Uncertainty Speak 37- 44 F8.3 mas EWOff Relative position East-West 46- 50 F5.3 mas e_EWOff Uncertainty in EWOff 52- 59 F8.3 mas NSOff Relative position North-South 61- 65 F5.3 mas e_NSOff Uncertainty in NSOff 67- 68 I2 --- SChan Number of contributing spectral channels 70- 74 F5.3 km/s HPFW ? Half Power Full Width of fitted Gaussian (3) 76- 80 F5.3 km/s e_HPFW ? Uncertainty in HPFW 82- 83 I2 --- MNum ? Associated proper motion number (4)
Note (1): Maser identification number: The first digit represents the epoch number (1-4) The last number represents the Maser feature number (0-48) Note (2): The uncertainty in the radial velocity is assumed to be one-half channel (.21km/s) for features composed of three or fewer spots. Note (3): Quoted for features with line profiles fit to a Gaussian model. Note (4): For features with measured proper motions, entries indicate the identification numbers of motions, as enumerated in Table 3.
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 4 A4 --- IRS Object name (IRS1 or IRS3) (G1) 6- 7 I2 --- MNum Associated proper motion number 9 A1 --- f_MNum [cd] Flag on MNum (1) 11- 15 F5.2 km/s RV Radial velocity 17- 24 F8.3 mas EWOff Relative position East-West 26- 33 F8.3 mas NSOff Relative position North-South 35- 40 F6.2 km/s EWVel Measured East-West proper motion expressed as a velocity (2) 42- 45 F4.2 km/s e_EWVel Uncertainty in EWVel 47- 52 F6.2 km/s NSVel Measured North-South proper motion expressed as a velocity (2) 54- 57 F4.2 km/s e_NSVel Uncertainty in NSVel 59- 62 A4 --- ID1 Epoch1 maser feature identification number 64- 67 A4 --- ID2 Epoch2 maser feature identification number 69- 72 A4 --- ID3 Epoch3 maser feature identification number 74- 77 A4 --- ID4 Epoch4 maser feature identification number
Note (1): Flag on associated proper motion number as follows: c = IRS3 motion 6 is zero because the corresponding feature was used to align the maps of the four epochs. d = IRS1 motion 12 corresponds to the maser feature used to align the maps of the four epochs. An offset is added to all the motions so that the net apparent motion of the IRS1 region is zero. Motion 12 corresponds to that offset. Note (2): Assuming a distance of 390pc.
Global notes: Note (G1): Nomenclature: Objects are identified as [SGH2002b] IRS1 N NN and [SGH2002b] IRS3 N NN in Simbad
History: * 06-Feb-2003: From electronic version of the journal * 29-Dec-2005 : Some MNum numbers were corrected in table2
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 06-Feb-2003
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

catalogue service

© UDS/CNRS

Contact