J/ApJ/769/20 22GHz H2O maser survey toward IR sources (Yung+, 2013)
Water maser survey on AKARI and IRAS sources: a search for "low-velocity" water
fountains.
Yung B.H.K., Nakashima J.-I., Imai H., Deguchi S., Henkel C., Kwok S.
<Astrophys. J., 769, 20 (2013)>
=2013ApJ...769...20Y 2013ApJ...769...20Y
ADC_Keywords: Masers ; Photometry, infrared ; Stars, giant ; Radio lines
Keywords: infrared: stars; masers; stars: AGB and post-AGB; stars: evolution;
stars: winds, outflows
Abstract:
We present the results of a 22GHz H2O maser survey toward a new
sample of asymptotic giant branch (AGB) and post-AGB star candidates.
Most of the objects are selected for the first time based on the AKARI
data, which have high flux sensitivity in the mid-infrared ranges. We
aim at finding H2O maser sources in the transient phase between the
AGB and post-AGB stages of evolution, where the envelopes start to
develop large deviations from spherical symmetry. The observations
were carried out with the Effelsberg 100m radio telescope. Among 204
observed objects, 63 detections (36 new) were obtained. We found four
objects that may be "water fountain" sources (IRAS 15193+3132,
IRAS 18056-1514, OH 16.3-3.0, and IRAS 18455+0448). They possess an
H2O maser velocity coverage much smaller than those in other known
water fountains. However, the coverage is still larger than that of
the 1612MHz OH maser. It implies that there is an outflow with a
higher velocity than the envelope expansion velocity (typically
≤25km/s), meeting the criterion of the water fountain class. We
suggest that these candidates are possibly oxygen-rich late AGB or
early post-AGB stars in a stage of evolution immediately after the
spherically symmetric AGB mass loss has ceased.
Description:
The observation was performed with the Effelsberg 100m radio telescope
from 2011 November 30 to December 6. An 18-26GHz HEMT receiver and
fast Fourier transform spectrometer were used in the front end and the
back end, respectively. The rest frequency of the 616->523
transition line of H2O molecules was adopted as 22.235080GHz. At
this frequency, the FWHM of the beam was about 40".
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 113 204 Parameters of the observing targets
table3.dat 69 63 Parameters of the H2O maser detections
table4.dat 20 141 Parameters of the non-detections
refs.dat 90 60 References
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See also:
II/298 : AKARI/FIS All-Sky Survey Point Source Catalogues (ISAS/JAXA, 2010)
II/297 : AKARI/IRC mid-IR all-sky Survey (ISAS/JAXA, 2010)
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
II/125 : IRAS catalogue of Point Sources, Version 2.0 (IPAC 1986)
J/ApJ/741/94 : VLBA obs. of H20 maser in IRAS 18286-0959 (Yung+, 2011)
J/PASJ/62/525 : SiO maser survey off the Galactic Plane (Deguchi+, 2010)
J/ApJ/678/96 : Extragalactic H2O masers (Braatz+, 2008)
J/ApJ/669/446 : Observations of SiO masers (Nakashima+, 2007)
J/ApJ/669/424 : H2O maser emissions of IRAS 19134+2131 (Imai+, 2007)
J/ApJ/658/1096 : H2O maser classification (Deacon+, 2007)
J/PASJ/56/765 : SiO maser survey of IRAS sources (Deguchi+, 2004)
J/PASJ/55/229 : SiO maser survey of cold IRAS sources (Nakashima+, 2003)
J/PASJ/55/203 : SiO maser survey toward inner Galactic disk (Nakashima+, 2003)
J/A+A/366/481 : ATCA/VLA OH 1612 MHz survey. III. (Sevenster+, 2001)
J/A+AS/127/185 : SiO masers in OH/IR stars, proto-PN and PN (Nyman+ 1998)
J/A+AS/119/459 : Search for OH maser emission (te Lintel Hekkert+ 1996)
J/ApJS/106/463 : SiO maser sources (Jiang+ 1996)
J/A+A/299/755 : Stellar evolution. II. Post-AGB (Bloecker+, 1995)
J/A+AS/111/237 : OH detections from circumstellar shells (Lewis+, 1995)
J/ApJS/93/549 : Arecibo 1612 MHz survey supplement (Lewis 1994)
J/ApJS/89/189 : IRAS PSC new OH/IR stars. III. (Chengalur+ 1993)
J/A+A/277/453 : OH maser survey of cool IRAS sources (David+ 1993)
J/A+AS/90/327 : IRAS point source 1612MHz OH survey (te Lintel Hekkert+ 1991)
http://www.ir.isas.jaxa.jp/AKARI/Observation/PSC/Public/ : AKARI PS cat.
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- Name Object name
17- 18 I2 h RAh Hour of Right Ascension (J2000)
20- 21 I2 min RAm Minute of Right Ascension (J2000)
23- 27 F5.2 s RAs Second of Right Ascension (J2000)
29 A1 --- DE- Sign of the Declination (J2000)
30- 31 I2 deg DEd Degree of Declination (J2000)
33- 34 I2 arcmin DEm Arcminute of Declination (J2000)
36- 39 F4.1 arcsec DEs Arcsecond of Declination (J2000)
41- 45 F5.2 --- IC12 ? IRAS [12]-[25] micron band color index
47- 51 F5.2 --- IC23 ? IRAS [25]-[60] micron band color index
53- 57 F5.2 --- AC12 ? AKARI [09]-[18] micron band color index
59- 63 F5.2 --- AC23 ? AKARI [18]-[65] micron band color index
65- 69 F5.1 km/s VOHb [-95/135]? Local Standard of Rest velocity of
blueshifted OH maser profile (1)
71 A1 --- f_VOHb [N] Non-detection of VOHb (2)
73- 77 F5.1 km/s VOHr ? Local Standard of Rest velocity of redshifted
OH maser profile (1)
79 A1 --- f_VOHr [Ni] Note on VOHr (2)
81- 82 I2 --- Ref1 ? Reference for OH maser velocities
(see refs.dat file)
84- 89 F6.2 --- VSiO1 [-74/186]? Local Standard of Rest velocity of SiO
(v=1,J=1-0) maser peak
91 A1 --- f_VSiO1 [Nj] Note on VSiO1 (2)
94- 99 F6.2 --- VSiO2 ? Local Standard of Rest velocity of SiO
(v=2,J=1-0) maser peak
101 A1 --- f_VSiO2 [N] Non-detection of VSiO2 (2)
103-105 A3 --- Ref2 Reference(s) for SiO maser velocities
(see refs.dat file)
107-113 A7 --- Cat [a-h] Source category (3)
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Note (1): Of a double-peaked profile. For a single-peaked profile, the VLSR
is recorded as OHVbp, no matter it is really "blueshifted" or not.
Note (2): Flag as follows:
N = Non-detection.
i = From our unpublished data of an OH maser observation conducted in year
2012, using the Effelsberg 100m radio telescope.
j = Imai et al. (2005ApJ...622L.125I 2005ApJ...622L.125I) found that W43A actually has a
biconical flow traced by SiO emission. The spectral velocity range is
from about 15-50km/s.
Note (3): Category as follows (see section 2.2 for further explanations):
a = Potential water fountains (WFs) and known WFs.
b = AKARI objects (DEC≥-20°) lying inside the post-AGB region in the
AKARI two-color diagram (Figure 1), with 0.5≤[09]-[18]≤4.5 and
-0.5≤[18]-[65]≤2.
c = AKARI objects (DEC≥-20°) lying inside the AGB region in the AKARI
two-color diagram (Figure 1), with -1≤[09]-[18]≤1.5 and
-3≤[18]-[65]≤-0.5.
d = IRAS objects (DEC≥-20°) selected from the AGB, post-AGB, or
redder regions (i.e., IIIa, IIIb, IV, V, and VIII) of the IRAS two-color
diagram studied by van der Veen & Habing (1988A&A...194..125V 1988A&A...194..125V), as
shown in Figure 2.
e = Known SiO maser sources not observed at 22GHz before. These objects are
most likely AGB to very early post-AGB stars.
f = H2O non-detections in Lewis (1997AJ....114.1602L 1997AJ....114.1602L).
g = H2O non-detections in Johnston et al. (1973ApJ...182...67J 1973ApJ...182...67J).
h = Other sources that do not belong to any of the above categories.
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- Name Object name
17- 22 F6.1 km/s Vbp [-123/73.5] VLSR of the blueshifted peak of
a double-peaked profile (1)
24- 28 F5.2 Jy Fbp [0.06/75.6] Flux density of the blueshifted
peak of a double-peaked profile (1)
30- 34 F5.1 km/s Vrp [-65/107]? VLSR of the redshifted peak of
a double-peaked profile (1)
36- 41 F6.2 Jy Frp [0.2/390]? Flux density of the redshifted
peak of a double-peaked profile (1)
43- 46 I4 km/s Vbe [-123/70] VLSR of the two ends of the whole
emission profile (2)
48- 50 I3 km/s Vre [-80/171] VLSR of the two ends of the whole
emission profile (2)
52- 58 F7.2 Jy.km/s Se [0.3/1021] Integrated flux of the whole
emission profile
60- 63 F4.2 10-2Jy rms [1.4/7.1] rms noise level
65- 69 A5 --- Ref Reference(s) for known detections
(see refs.dat file)
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Note (1): For a single-peaked or irregular profile, the brightest peak is
recorded in these columns, whether or not it is really
"blueshifted" or "redshifted".
Note (2): The cut-off is defined by the 3σ flux level.
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- Name Object name
17- 20 F4.2 cJy rms [2.3/9.3] rms noise level (in 10-2Jy)
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Byte-by-byte Description of file: refs.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Ref Reference code
4- 22 A19 --- BibCode Bibcode
24- 50 A27 --- Aut Author's name(s)
52- 90 A39 --- Comm Comment
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 02-Dec-2014