J/MNRAS/520/314 Polarization geometry of observed LOFAR pulsars (Wahl+, 2023)
Radio pulsar emission-beam geometry at low frequency LOFAR High-Band Survey
sources studied using Arecibo at 1.4 GHz and 327 MHz.
Wahl H., Rankin J., Venkataraman A., Olszanski T.
<Mon. Not. R. Astron. Soc. 520, 314-321 (2023)>
=2023MNRAS.520..314W 2023MNRAS.520..314W (SIMBAD/NED BibCode)
ADC_Keywords: Pulsars ; Photometry ; Spectroscopy ; Velocity dispersion ;
Rotational velocities ; References ; Millimetric/submm sources ;
Radio sources ; Magnetic fields ; Polarization
Keywords: polarization - radiation mechanisms: non-thermal - pulsars: general -
ISM: structure
Abstract:
This paper continues our study of radio pulsar emission-beam
configurations with the primary intent of extending study to the
lowest possible frequencies. Here, we focus on a group of 133 more
recently discovered pulsars, most of which were included in the
(100-200 MHz) LOFAR High-Band Survey, observed with Arecibo at 1.4 GHz
and 327 MHz, and some observed at decametre wavelengths. Our analysis
framework is the core/double-cone beam model, and we took opportunity
to apply it as widely as possible, both conceptually and
quantitatively, while highlighting situations where modelling is
difficult, or where its premises may be violated. In the great
majority of pulsars, beam forms consistent with the core/double-cone
model were identified. Moreover, we found that each pulsar's beam
structure remained largely constant over the frequency range
available; where profile variations were observed, they were
attributable to different component spectra and in some instances to
varying conal beam sizes. As an Arecibo population, many or most of
the objects tend to fall in the Galactic anticenter region and/or at
high Galactic latitudes, so overall it includes a number of nearer,
older pulsars. We found a number of interesting or unusual
characteristics in some of the pulsars that would benefit from
additional study. The scattering levels encountered for this group are
low to moderate, apart from a few pulsars lying in directions more
towards the inner Galaxy.
Description:
A radio pulsar emission-beam model with a central 'core' pencil beam
and two concentric conal beams has proven useful and largely
successful both qualitatively and quantitatively in efforts to model
the beam geometry at frequencies around 1 GHz (Rankin et al.
1993ApJ...405..285R 1993ApJ...405..285R and appendix 1993ApJS...85..145R 1993ApJS...85..145R). Few attempts,
however, have been made to explore the systematics of pulsar beam
geometry over the entire radio spectrum. Here, we present analyses
aimed at elucidating the multiband beam geometry of a brighter group
of 'J' pulsars within the Arecibo sky, most of which with observations
down to the 100-MHz band (similarly to Paper I Olszanski et al.
2022MNRAS.517.1189O 2022MNRAS.517.1189O and II Rankin et al. 2023MNRAS.519.3872R 2023MNRAS.519.3872R, we also
study pulsars at 1.4-GHz and 327-MHz LOFAR Arecibo observations).
We observe pulsars in P-band and L-band Arecibo receivers (and either
the Wideband Arecibo Pulsar Processors WAPPs or Mock spectrometer
backends). For 133 known pulsars, we preset in tablea1.dat, dispersion
and rotation measures, our MJD, number of pulses and used bins.
Literature references for low frequency ≲100 MHz aand poor L/P-bands
data are provided. Next as described in section 3 and 4, we make use
of a full recent core/double-cone geometric beam model to compute
geometric properties for our pulsars sample. Results are available in
tablea3.dat. More related to section 3 work, we present in
tablea2.dat, the physical spin down properties of our pulsars sample,
(on period, energy, magnetic power) mostly equivalent to ATNF pulsar
catalogue.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 114 133 *Arecibo observation and pulsation informations
of our pulsars sample
tablea2.dat 60 133 The physical spin down parameters of our pulsars
sample
tablea3.dat 140 133 Core/double cone emission-beam model geometrical
properties
--------------------------------------------------------------------------------
Note on tablea1.dat: The reference parameters for PSRs J0245+1433, J0848+1640,
J0928+0614, J1147+0829 and J1844+0036, which do not appear in the ATNF Pulsar
Catalogue, were obtained from the discoverers (Kevin Stovall, private
communication) as refinements to Deneva et al. (2013ApJ...775...51D 2013ApJ...775...51D).
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See also:
J/MNRAS/489/1543 : Arecibo polarimetric single-pulse survey (Olszanski+, 2019)
J/MNRAS/474/4629 : Polarimetry of 600 pulsars from 1.4GHz obs. (Johnston+,2018)
J/MNRAS/391/1210 : Characteristics of energetic pulsars (Weltevrede+, 2008)
J/MNRAS/372/777 : Parkes Multibeam Pulsar Survey. VI. (Lorimer+, 2006)
J/ApJ/892/76 : The GBNCC pulsar survey. V. Pulsar census (McEwen+, 2020)
J/ApJ/605/759 : Multifrequency obs. of radio pulse broadening (Bhat+, 2004)
J/A+A/635/A76 : LOFAR census of pulsars at low frequencies
(Bondonneau+, 2020)
J/A+A/635/A75 : LOFAR census of non-recycled pulsars sample (Bilous+, 2020)
J/A+A/591/A134 : LOFAR census of non-recycled pulsars (Bilous+, 2016)
J/A+A/586/A92 : Pulse profiles of 100 radio pulsars (Pilia+, 2016)
J/A+A/469/607 : Pulsar subpulse modulation properties at 92cm
(Weltevrede+, 2007)
J/AZh/87/238 : Pulse profiles of radio pulsars at 102 and 111MHz
(Malov+, 2010)
J/AZh/84/685 : Scattering of pulsar radio emission (Kuz'min+, 2007)
B/psr : ATNF Pulsar Catalogue (Manchester+, 2005)
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Name Pulsar name designation as JHHMM+DDMM (Pulsar)
12- 17 F6.4 s P Barycentric period of the pulsar (P)
19- 24 F6.2 pc/cm3 DM Pulsar dispersion measure (DM)
26- 31 F6.1 rad/m2 RM ? Pulsar rotation measure (RM)
33- 37 I5 d MJDl ? Modified Julian date in L-band frequencies
(JD-2400000.5) (MJD)
39- 42 A4 --- n_MJDl Note on MJDl of J0538+2817 and J1813+1822
pulsars
44- 49 I6 --- Npl ? Number of observed pulses at L-band
frequencies (Npulses) (1)
51- 54 I4 --- Nbl ? Number of bins used to observe the pulsar in
L-band frequencies (Bins) (2)
56- 65 A10 --- Refl Reference for L-band data in case of our poor
or missing Arecibo observations (3)
67- 71 I5 --- MJDp ? Modified Julian date in P-band frequencies
(JD-2400000.5) (MJD)
73- 78 I6 --- Npp ? Number of observed pulses at P-band
frequencies (Npulses) (4)
80- 83 I4 --- Nbp ? Number of bins used to observe the pulsar in
P-band frequencies (Bins) (2)
85- 95 A11 --- Refp Reference for P-band data in case of our poor
or missing Arecibo observations (5)
97-114 A18 --- Ref100 For low frequency ≲100 MHz observations
please consult the paper of origin as
referenced (References) (6)
--------------------------------------------------------------------------------
Note (1): We present observations carried out using the upgraded Arecibo
Telescope in Puerto Rico with its Gregorian feed system L-band
1100-1700 MHz receiver, and either the Wideband Arecibo Pulsar
Processors (WAPPs) or Mock spectrometer backends. At L-band four
nominally 100 MHz bands centred at 1170, 1420, 1520, and 1620 MHz
were used, and the lower three were usually free enough of radio
frequency interference (RFI) such that they could be added together
to give about 300-MHz bandwidth nominally at 1400 MHz.
Note (2): The four Stokes parameters were calibrated from the auto- and
cross-voltage correlations computed by the spectrometers, corrected
for interstellar Faraday rotation, various instrumental polarization
effects, and dispersion. The resolutions of the observations are
usually about a milliperiod as indicated by the sample numbers.
Note (3): Where our Arecibo observations were poor or missing we made use of
other published compendia as follows:
SBM+22 = For pulsar J0030+0451, Spiewak et al.
(2022PASA...39...27S 2022PASA...39...27S)
Burgay+06 = For pulsar J0843+0719, Burgay et al.
(2006MNRAS.368..283B 2006MNRAS.368..283B)
Janssen+09 = For pulsar J1937+2950, Janssen et al.
(2009A&A...498..223J 2009A&A...498..223J)
Lynch2013 = For pulsar J2033+0042, Lynch et al.
(2013ApJ...763...81L 2013ApJ...763...81L)
Note (4): We present observations carried out using the upgraded Arecibo
Telescope in Puerto Rico with its Gregorian feed system P-band
327-MHz receiver, and either the Wideband Arecibo Pulsar
Processors (WAPPs) or Mock spectrometer backends. At P-band four
12.5-MHz bands were used across the 50 MHz available.
Note (5): Where our Arecibo observations were poor or missing we made use of
other published compendia as follows:
Lynch2013 = For pulsar J0348+0432, Lynch et al.
(2013ApJ...763...81L 2013ApJ...763...81L)
Mcewen = McEwen et al. 2020ApJ...892...76M 2020ApJ...892...76M, Cat. J/ApJ/892/76,
11 occurences in our sample
Stairs99 = For pulsar J0621+1002, Stairs et al.
(1999ApJS..123..627S 1999ApJS..123..627S)
Foster+95 = For pulsars J1811+0702 and J1822+0705, Foster et al.
(1995ApJ...454..826F 1995ApJ...454..826F)
Champion+05 = For pulsar J1843+2024, Champion et al.
(2005MNRAS.363..929C 2005MNRAS.363..929C)
Janssen+09 = For pulsar J1937+2950, Janssen et al.
(2009A&A...498..223J 2009A&A...498..223J)
Barr+13 = For pulsars J1959+3620, Barr et al.
(2013MNRAS.435.2234B 2013MNRAS.435.2234B)
Note (6): References for ≲100 MHz are as follows:
BKK+ = Bilous et al. (2016A&A...591A.134B 2016A&A...591A.134B, Cat. J/A+A/591/A134),
75 occurences in our sample
KTSD = Kumar et al. (2023AAS...24232906K),
2 occurences in our sample
KZUS = Kravtsov et al. (2022MNRAS.512.4324K 2022MNRAS.512.4324K), 1 occurence in our
sample
MM10 = Malov & Malofeev (2010ARep...54..210M 2010ARep...54..210M, Cat. J/AZh/87/238),
4 occurences in our sample
PHS+ = Pilia et al. (2016A&A...586A..92P 2016A&A...586A..92P, Cat. J/A+A/586/A92)
PRAO = Pushchino Radio Astronomy Observatory by Valerij Maloveev
to ask for private communication, 3 occurences in our sample
ZVKU = Zakharenko et al. (2013MNRAS.431.3624Z 2013MNRAS.431.3624Z), 6 occurences in
our sample
-------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Name Pulsar name designation as JHHMM+DDMM
(Pulsar)
12- 17 F6.4 s P Barycentric period of the pulsar (P)
19- 27 F9.5 10-15 dP/dt ? Period derivative spin-down rate (dP/dt)
29- 35 F7.3 10+25W dE/dt ? The spin-down energy loss rate (dE/dt)
37- 42 F6.1 Myr tau ? Pulsar scattering spin-down age as
P/[dP/dt] (τ)
44- 51 F8.5 10+12gauss Bsurf ? The surface magnetic flux density of the
pulsar (Bsurf)
53- 56 F4.1 --- B12/P2 ? The pulsar acceleration potential
parameter as (|Bsurf|*10-12/P2) as
the ability of the pulsar to accelerate
charged particles (B12/P2)
58- 60 F3.1 --- 1/Q ? The reciprocal Q parameter as 1/Q =
0.5(dP/dt)0.4-15/P-1.1 of Beskin et
al. 1993ppm..book.....B 1993ppm..book.....B (1/Q)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Name Pulsar name designation as JHHMM+DDMM (Pulsar)
12- 17 A6 --- Class Profile class of the pulsar cone emission-beam
as described in section 3 (Class) (1)
19 A1 --- n_alpha1G Note b on magnetic colatitude of the beam
α (2)
21- 22 A2 --- f_alpha1G Flag on α values as ! means proportional
to and #? means approximatively equal to
24- 27 F4.1 deg alpha1G ? Magnetic colatitude of the pulsar beam for
the 1GHz geometry regime is angle between the
rotation and magnetic axes (alpha1GHz)
29- 31 A3 --- f_R1G Flag on the polarization position angle PPA
sweep rate R (3)
33- 38 F6.2 --- R1G ? The pulsar polarization position angle PPA
sweep rate R for the 1GHz geometry regime
(R1GHz)
40 A1 --- f_beta1G Flag on sightline impact angle beta for values
as ! means proportional to
42- 46 F5.1 deg beta1G ? The pulsar sightline impact angle
β=sinα/R showing how the sightline
crosses the beam for the 1GHz geometry regime
(β1GHz) (4)
48- 49 A2 --- f_Wc1.4G Flag on core width Wc (3)
51- 54 F4.1 deg Wc1.4G ? The pulsar core width for the 1.4 GHz
beam-sizes band regime (Wc1.4GHz)
56 A1 --- f_Wi1.4G Flag on Wi for ! means proportional to
58- 62 F5.1 deg Wi1.4G ? The pulsar inner conal component width for
the 1.4 GHz beam-sizes band regime (Wi1.4GHz)
64- 67 F4.1 deg ri1.4G ? The pulsar inner beam radii for the 1.4 GHz
beam-sizes band regime (ρi1.4GHz)
69 A1 --- f_Wo1.4G Flag on Wo for ! means proportional to
71- 73 I3 deg Wo1.4G ? The pulsar outer conal component width for
the 1.4 GHz beam-sizes band regime (Wo1.4GHz)
75- 78 F4.1 deg ro1.4G ? The pulsar outer beam radii for the 1.4 GHz
beam-sizes band regime (ρo1.4GHz)
80- 81 A2 --- f_Wc327M Flag on core width Wc (3)
83- 86 F4.1 deg Wc327M ? The pulsar core width for the 327 MHz
beam-sizes band regime (Wc327MHz)
88- 89 A2 --- f_Wi327M Flag on Wi327M (3)
91- 95 F5.1 deg Wi327M ? The pulsar inner conal component width for
the 327 MHz beam-sizes band regime (Wi327MHz)
97-100 F4.1 deg ri327M ? The pulsar inner beam radii for the 327 MHz
beam-sizes band regime (ρiWi327MHz_)
102-103 A2 --- f_Wo327M Flag on Wo327M (3)
105-109 F5.1 deg Wo327M ? The pulsar outer conal component width for
the 327 MHz beam-sizes band regime (Wo327MHz)
111-114 F4.1 deg ro327M ? The pulsar outer beam radii for the 327 MHz
beam-sizes band regime (ρo327MHz)
116 A1 --- f_Wi100M Flag on Wi100M for ! means proportional to
118-122 F5.1 deg Wi100M ? The pulsar inner conal component width for
the lowest frequency values in the 100-MHz or
below bands beam-sizes band regime
(Wi<∼100MHz)
124-127 F4.1 deg ri100M ? The pulsar inner beam radii for the lowest
frequency values in the 100-MHz or below bands
beam-sizes band regime (ρi<∼100MHz)
129 A1 --- f_Wo100M Flag on Wo100M for ! means proportional to
131-135 F5.1 deg Wo100M ? The pulsar outer conal component width for
the lowest frequency values in the 100-MHz or
below bands beam-sizes band regime
(Wo<∼100MHz)
137-140 F4.1 deg ro100M ? The pulsar outer beam radii for the lowest
frequency values in the 100-MHz or below bands
beam-sizes band regime (ρo<∼100MHz)
--------------------------------------------------------------------------------
Note (1): As explained in section 3, Canonical pulsar average profiles are
observed to have up to five components, leading to the conception
of the core/double-cone beam model. Pulsar profiles then divide
into two families depending on whether core or conal emission is
dominant at about 1 GHz :
Core single St profiles consist of an isolated core component
often flanked by a pair of outriding conal components at high
frequency.
Triple T profiles show a core and conal component pair over a
wide band.
Five-component M profiles have a central core component flanked
by both an inner and outer pair of conal components.
By contrast, conal profiles can be single Sd or double D when a
single cone is involved, or triple cT or quadruple cQ when the
sightline encounters both conal beams. Outer cones tend to have an
increasing radius with wavelength, while inner cones tend to show
little spectral variation. Periodic modulation often associated with
subpulse 'drift' is a usual property of conal emission and assists
in defining a pulsar's beam configuration.
Note (2): Core radiation is found empirically to have a bivariate Gaussian
(von Mises) beamform such that its 1-GHz (and often invariant) width
measures α but provides no sightline impact angle information.
If a pulsar has a core component, we attempt to use its width at
around 1-GHz to estimate the magnetic colatitude α, and when
this is possible the α value is bolded as 'b' in our table.
Note (3): Flag to indicates, ! means proportional to and #? means
approximatively equal to, inf for infinite values ? or ?? questionable
values.
Note (4): As explicited in section 3, the sightline-circle radius (the angle
between the rotation axis and the observer's sightline) Zeta, where
the sightline impact angle β = Zeta - α.
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History:
From electronic version of the journal
References:
Olszanski et al., Paper I 2022MNRAS.517.1189O 2022MNRAS.517.1189O
Rankin et al., Paper II 2023MNRAS.519.3872R 2023MNRAS.519.3872R
(End) Luc Trabelsi [CDS] 27-Feb-2026