J/AJ/135/588 Arecibo legacy fast ALFA survey V. (Saintonge+, 2008)
The Arecibo Legacy Fast Alfa Survey.
V. The H I source catalog of the Anti-Virgo region at δ = +27°.
Saintonge A., Giovanelli R., Haynes M.P., Hoffman G.L., Kent B.R.,
Martin A.M., Stierwalt S., Brosch N.
<Astron. J., 135, 588-604 (2008)>
=2008AJ....135..588S 2008AJ....135..588S
ADC_Keywords: Surveys ; H I data ; Galaxies, radio ; Cross identifications
Keywords: catalogs - galaxies: distances and redshifts - galaxies: photometry
galaxies: spiral - radio lines: galaxies - surveys
Abstract:
We present a second catalog of HI sources detected in the Arecibo
Legacy Fast ALFA Survey. We report 488 detections over 135deg2,
within the region of the sky having 22<RA<03 and +26<DE<+28. We
present here the detections that have either (a) S/N>6.5, where the
reliability of the catalog is better than 95% or (b) 5.0<S/N<6.5 and a
previously measured redshift that corroborates our detection. Of the
488 objects presented here, 49 are high-velocity clouds or clumps
thereof with negative heliocentric recession velocities. These clouds
are mostly very compact and isolated, while some of them are
associated with large features such as Wright's Cloud or the northern
extension of the Magellanic Stream. The remaining 439 candidate
detections are identified as extragalactic objects and have all been
matched with optical counterparts. Five of the six galaxies detected
with MHI<107.5 solMass are satellites of either the NGC672/IC1727
nearby galaxy pair or their neighboring dwarf irregular galaxy NGC784.
The data of this catalog release include a slice through the
Pisces-Perseus foreground void, a large nearby underdensity of
galaxies. We report no detections within the void, where our catalog
is complete for systems with HI masses of 108M☉.
Description:
The Arecibo Legacy Fast ALFA Survey (ALFALFA) is an on-going project
conducted at the Arecibo Observatory, using the 305m telescope and the
seven-beam ALFA receiver. Observations were made between 2005 August
and November and required just over 100h of telescope time.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 337 488 HI Candidate Detections
table2.dat 69 11 Detections in the NGC672 and NGC784 Groups
table3.dat 38 12 Detections of High Velocity Clouds (HVCs)
Previously Reported
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See also:
VIII/77 : HI spectral properties of galaxies (AGC) (Springob+, 2005)
VIII/73 : HI Parkes All Sky Survey Catalogue (HIPASS) (Meyer+, 2004)
J/AJ/130/2613 : The Arecibo Legacy Fast ALFA survey. II (Giovanelli+, 2005)
J/AJ/133/2569 : Arecibo legacy fast ALFA survey III. (Giovanelli+, 2007)
J/AJ/136/713 : Arecibo legacy fast ALFA survey. VI. (Kent+, 2008)
J/MNRAS/357/819 : Colours and HI line observations in Virgo (Sabatini+, 2005)
J/AJ/113/905 : HI observations of galaxies (Pantoja+ 1997)
http://arecibo.tc.cornell.edu/hiarchive : ALFALFA data access
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- --- [2-]
3- 5 I3 --- ALFALFA2 Catalog entry number (2-NNN)
7- 12 I6 --- AGC Arecibo General Catalog number (1)
14- 15 I2 h RAh HI Hour of Right Ascension (J2000) (2)
17- 18 I2 min RAm HI Minute of Right Ascension (J2000) (2)
20- 23 F4.1 s RAs HI Second of Right Ascension (J2000) (2)
25 A1 --- DE- HI Declination sign (J2000) (2)
26- 27 I2 deg DEd HI Degree of Declination (J2000) (2)
29- 30 I2 arcmin DEm HI Arcminute of Declination (J2000) (2)
32- 33 I2 arcsec DEs HI Arcsecond of Declination (J2000) (2)
35- 36 I2 h RAOh ? Optical Right Ascension (J2000) (3)
38- 39 I2 min RAOm ? Optical Right Ascension (J2000) (3)
41- 44 F4.1 s RAOs ? Optical Right Ascension (J2000) (3)
46 A1 --- DEO- Optical Declination sign (J2000)(3)
47- 48 I2 deg DEOd ? Optical Declination (J2000) (3)
50- 51 I2 arcmin DEOm ? Optical Declination (J2000) (3)
53- 54 I2 arcsec DEOs ? Optical Declination (J2000) (3)
56- 60 I5 km/s cz Heliocentric velocity of the HI source (4)
62- 64 I3 km/s W50 Velocity width at 50% level (5)
66- 68 I3 km/s e_W50 Estimated error in W50
70- 75 F6.2 Jy.km/s Fc Integrated flux density (6)
77- 80 F4.2 Jy.km/s e_Fc Estimated error in Fc
82- 86 F5.1 --- S/N Signal-to-noise ratio of detection (7)
88- 91 F4.2 mJy rms Noise figure of spatially integrated
spectral profile (8)
93- 97 F5.1 Mpc Dist ? Adopted distance (9)
99-103 F5.2 [solMass] logM ? Log of HI mass (10)
105 I1 --- Qual Source quality code (11)
107-337 A231 --- Note Additional comments for source
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Note (1): The AGC entry (Cat. VIII/77) normally corresponds to an optical
counterpart except in the cases of HI sources which cannot be
associated with an optical object with any high degree of probability.
Numbers lower than 1000 are UGC number (Cat. VII/26).
Note (2): Of the HI source, after correction for systematic telescope
pointing errors, which are on the order of 20". The accuracy of the
HI positions depends on source strength. On average, the positional
accuracy is about 19".
Note (3): Optical galaxy found to provide a reasonable optical counterpart.
Quality of centroids is estimated to be ∼2" or better. The assessment
of optical identification is based on spatial proximity, optical
redshift (if available), morphology and color. For sources with no
discernible optical counterpart and those for which such assignment
is ambiguous, due to the presence of more than one equally possible
optical counterpart, no optical position is listed.
Note (4): Measured as the midpoint between the channels at which the flux
density drops to 50% of each of the two peaks (or of one, if only one
is present) at each side of the spectral feature.
Note (5): This value is corrected for instrumental broadening. No
corrections due to turbulent motions, disk inclination or
cosmological effects are applied.
Note (6): Measured on the integrated spectrum, obtained by spatially
integrating the source image over a solid angle of at least 7'x7'
and dividing by the sum of the survey beam values over the same
set of image pixels.
Note (7): Estimated as S/N=(1000Fc/W50)(wsmo1/2/rms). Where wsmo is
either W50/(2x10) for W50<400km/s or 400/(2x10)=20 for W50≥400km/s
[wsmo is a smoothing width expressed as the number of spectral
resolution bins of 10km/s bridging half of the signal width].
Note (8): The rms as measured over the signal- and rfi-free portions of the
spectrum, after Hanning smoothing to a spectral resolution of 10km/s.
Note (9): For objects with cz>6000km/s, the distance is simply
czcmb/H0; czcmb is the recession velocity measured in the Cosmic
Microwave Background reference frame and H0 is the Hubble constant,
for which we use a value of 70km/s/Mpc. For objects of lower czcmb,
we use the peculiar velocity model for the local universe of Masters
(Giovanelli et al., Paper II, 2005, Cat. J/AJ/130/2613), which is
based on data from the SFI++ catalog of galaxies (Springob et al.,
2007, Cat. J/ApJS/172/599).
Note (10): Obtained by using the expression MHI=2.356x105Dist2Fc.
Note (11): Quality code as 1, 2 or 9:
1 = refers to sources of S/N and general qualities that make it a
reliable detection. See text for additional details.
2 = refers to sources of low S/N (<6.5), which would ordinarily not be
considered reliable detections by the criteria set for code 1.
9 = refers to objects assumed to be HVCs; no estimate of their
distances is made.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- AGC AGC catalog identification number
8- 13 A6 --- OName NGC, IC or [KK98a] number
15- 16 I2 h RAh HI Hour of Right Ascension (J2000)
17- 18 I2 min RAm HI Minute of Right Ascension (J2000)
19- 22 F4.1 s RAs HI Second of Right Ascension (J2000)
23 A1 --- DE- HI Declination sign (J2000)
24- 25 I2 deg DEd HI Degree of Declination (J2000)
26- 27 I2 arcmin DEm HI Arcminute of Declination (J2000)
28- 29 I2 arcsec DEs HI Arcsecond of Declination (J2000)
31- 33 I3 km/s cz Heliocentric recession velocity
35- 37 I3 km/s W50 Velocity width at 50% level
39- 44 F6.2 Jy.km/s Fc Integrated flux density
46- 48 F3.1 Mpc Dist ?=- Calculated distance using the peculiar
velocity model
50- 52 F3.1 Mpc Distl ? Distance from litterature (1)
53 A1 --- n_Distl [a] Remark on Distance (2)
55- 58 F4.2 [solMass] logM ? Log of HI mass estimated from Dist
60- 63 F4.2 [solMass] logMl Log of HI mass estimated from Distl
64 A1 --- n_logMl [b] means HI mass of the object, if at the
distance of NGC784 of 5.0Mpc
66- 69 A4 --- Group Group Membership
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Note (1): Distances found in the literature and assigned on the basis of
primary distance indicators or group membership (Huchtmeier et al.,
2000, Cat J/A+AS/141/469; Karachentsev et al., 2003, Cat.
J/A+A/398/479, Karachentsev et al., 2004, Cat. J/AJ/127/2031).
Note (2): No association between the HI detection and an optical galaxy
which is part of the NGC784 group has been made. This object is likely
to be of Galactic origin, and therefore a distance from the peculiar
velocity model is not warranted.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name HVC catalogs identification
8- 12 A5 --- Cat Catalog reference (1)
14- 15 I2 h RAh HI Hour of Right ascension (J2000)
16- 19 F4.1 min RAm HI Minute of right ascension (J2000)
20 A1 --- DE- HI Declination sign (J2000)
21- 22 I2 deg DEd HI Degree of Declination (J2000)
23- 24 I2 arcmin DEm HI Arcminute of declination (J2000)
26- 29 I4 km/s v(LSR) Local Standard of Rest (LSR) velocity
31- 34 I4 Jy.km/s F ?=- Integrated flux density
36- 38 A3 --- ALFALFA Yes or No for sources in ALFALFA
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Note (1): HVC catalogs as follows:
WW91 = Wakker & van Woerden, 1991A&A...250..509W 1991A&A...250..509W (WV NNN in Simbad)
DBB02 = de Heij et al., 2002A&A...391..159D 2002A&A...391..159D, Cat. J/A+A/391/159 ([DBB2002]
NNN in Simbad)
L02 = Lockman et al., 2002, Cat. J/ApJS/140/331, ID=119 in table 4
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History:
From electronic version of the journal
References:
Giovanelli et al., Paper I 2005AJ....130.2598G 2005AJ....130.2598G
Giovanelli et al., Paper II 2005AJ....130.2613G 2005AJ....130.2613G, Cat. J/AJ/130/2613
Giovanelli et al., Paper III 2007AJ....133.2569G 2007AJ....133.2569G, Cat. J/AJ/133/2569
Saintonge et al., Paper IV 2007AJ....133.2087S 2007AJ....133.2087S
Kent et al., Paper VI 2008AJ....136..713K 2008AJ....136..713K, Cat. J/AJ/136/713
Kent et al., Paper VII 2009ApJ...691.1595K 2009ApJ...691.1595K
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 15-Jul-2009