J/A+A/626/A104 LOTAAS pulsar discoveries (Sanidas+, 2019)
The LOFAR Tied-Array All-Sky Survey (LOTAAS):
Survey overview and initial pulsar discoveries.
Sanidas S., Cooper S., Bassa C.G., Hessels J.W.T., Kondratiev V.I.,
Michilli D., Stappers B.W., Tan C.M., Van Leeuwen J., Cerrigone L.,
Fallows R.A., Iacobelli M., Orru E., Pizzo R.F., Shulevski A.,
Toribio M.C., Ter Veen S., Zucca P., Bondonneau L., Griessmeier J.-M.,
Karastergiou A., Kramer M., Sobey C.
<Astron. Astrophys., 626, A104 (2019)>
=2019A&A...626A.104S 2019A&A...626A.104S (SIMBAD/NED BibCode)
ADC_Keywords: Pulsars
Keywords: pulsars: general - methods: data analysis - methods: observational
Abstract:
We present an overview of the LOFAR Tied-Array All-Sky Survey (LOTAAS)
for radio pulsars and fast transients. The survey uses the high-band
antennas of the LOFAR Superterp, the dense inner part of the LOFAR
core, to survey the northern sky (δ>0°) at a central
observing frequency of 135MHz. A total of 219 tied-array beams
(coherent summation of station signals, covering 12 square degrees),
as well as three incoherent beams (covering 67 square degrees) are
formed in each survey pointing. For each of the 222 beams, total
intensity is recorded at 491.52 µs time resolution. Each
observation integrates for 1hr and covers 2592 channels from 119 to
151MHz. This instrumental setup allows LOTAAS to reach a detection
threshold of 1-5mJy for periodic emission. Thus far, the LOTAAS survey
has resulted in the discovery of 73 radio pulsars. Among these are two
mildly recycled binary millisecond pulsars (P=13 and 33ms), as well as
the slowest-spinning radio pulsar currently known (P=23.5s). The
survey has thus far detected 311 known pulsars, with spin periods
ranging from 4ms to 5.0s and dispersion measures from 3.0 to
217pc/cm3. Known pulsars are detected at flux densities consistent
with literature values. We find that the LOTAAS pulsar discoveries
have, on average, longer spin periods than the known pulsar
population. This may reflect different selection biases between LOTAAS
and previous surveys, though it is also possible that slower-spinning
pulsars preferentially have steeper radio spectra. LOTAAS is the
deepest all-sky pulsar survey using a digital aperture array; we
discuss some of the lessons learned that can inform the approach for
similar surveys using future radio telescopes such as the Square
Kilometre Array.
Description:
As of January 2019, the LOTAAS survey has discovered and confirmed 73
pulsars; in this overview paper, we present their properties. An up to
date list of LOTAAS discoveries is maintained online
(https://www.astron.nl/lotaas).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 98 73 LOTAAS pulsar discoveries and their properties
tablea1.dat 95 311 Known pulsars detected by LOTAAS
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See also:
B/psr : ATNF Pulsar Catalogue (Manchester+, 2005)
J/A+A/586/A92 : Pulse profiles of 100 radio pulsars (Pilia+, 2016)
J/A+A/591/A134 : LOFAR census of non-recycled pulsars (Bilous+, 2016)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- PSR PSR name (JHHMM+DD) (1)
10- 16 F7.4 s Pspin Spin period
18- 24 F7.3 pc/cm3 DM Dispersion measure
26- 30 F5.3 pc/cm3 e_DM rms uncertainty on DM
33- 34 I2 h RAh Right ascension (J2000)
36- 39 F4.1 min RAm Right ascension (J2000)
41- 43 F3.1 min e_RAm rms uncertainty on right ascension (J2000) (2)
45 A1 --- DE- Declination sign (J2000)
46- 47 I2 deg DEd Declination (J2000)
49- 50 I2 arcmin DEm Declination (J2000)
52 I1 arcmin e_DEm rms uncertainty on declination (J2000) (2)
54- 59 F6.2 deg GLON Galactic longitude
61- 66 F6.2 deg GLAT Galactic latitude
68- 71 F4.2 kpc dNE2001 Distance as predicted by the NE2001 mode
73- 75 I3 ms w50 Pulse FWHM
77- 98 A22 --- Com Comments (3)
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Note (1): Pulsar names are defined based on the tied-array beam (TAB) position
of full LOFAR core follow-up observations.
Note (2): Here, we use the full core tied-array beam (TAB) FWHM as the
positional uncertainty.
If the pulsar is mentioned elsewhere with a different name, the alternate
identification is provided in the comments.
Note (3): L-sps denotes pulsars found by the L-sps single pulse algorithm.
Pulsars denoted with P have been presented as independent discoveries by
the Puschino telescope.
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- PSR PSR name
12- 17 F6.4 s Pspin Detected spin period
19- 23 F5.1 pc/cm2 DM Dispersion measure
25- 27 F3.1 deg thetaTAB Offset between the known position of the
pulsars and the centre position of the
tied-array beam (TAB) where the pulsar
is detected
29- 31 F3.1 deg thetaSAP Offset between the known position of the
pulsars and the centre position of the
sub-array pointing (SAP) where the pulsar
is detected
33- 38 F6.1 --- sigma Signal-to-noise of the pulsars at 135MHz
40- 45 F6.1 mJy Su135 Estimated flux density of the pulsars at
135MHz before applying the correction factor
due to the offset in position
47- 49 F3.1 --- Sx135 ?=- Correction correction factor due to
the offset in position
51- 56 F6.1 mJy Sc135 ?=- Estimated flux density of the pulsars at
135MHz after applying the correction factor
due to the offset in position
58- 63 F6.1 mJy S400 ?=- Flux density at 400MHz
65- 70 F6.1 mJy S150 ?=- Flux density at 150MHz
72- 76 F5.2 --- alpha ?=- Spectral index as listed in PSRCAT v1.59
(Manchester et al. 2005, Cat. B/psr)
78- 84 F7.1 mJy Sexp135 ?=- Expected flux density at 135MHz
86- 95 A10 --- Notes Notes (1)
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Note (1): Notes as follows:
1 = Pulsars discovered by the GBNCC survey
(Stovall et al., 2014ApJ...791...67S 2014ApJ...791...67S)
2 = Pulsars discovered by the AO327 survey
(Deneva et al., 2013ApJ...775...51D 2013ApJ...775...51D)
3 = Pulsars previously not reported by other LOFAR censuses
(Pilia et al., 2016, Cat. J/A+A/586/A92;
Bilous et al., 2016, Cat. J/A+A/591/A134;
Kondratiev et al. 2016A&A...585A.128K 2016A&A...585A.128K)
4 = Pulsars not in v1.59 of the ATNF pulsar catalogue
(Manchester et al., 2005, Cat. B/psr)
5 = Pulsars with |DM|>2.0pc/cm3 compared to v1.54 of the
ATNF pulsar catalogue
6 = This pulsar has no precise position measurement. The pulsar is assumed to
be located at the centre of the detected tied-array beam (TAB) and only
the offset from the sub-array pointing (SAP) is considered for the flux
density value correction
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 07-Aug-2019