J/ApJ/934/L17 Keck/LRIS spectra of PSR J0952-0607 (Romani+, 2022)
PSR J0952-0607: the fastest and heaviest known Galactic neutron star.
Romani R.W., Kandel D., Filippenko A.V., Brink T.G., Zheng W.
<Astrophys. J., 934, L17 (2022)>
=2022ApJ...934L..17R 2022ApJ...934L..17R
ADC_Keywords: Pulsars; Spectra, optical; Stars, neutron
Keywords: Pulsars
Abstract:
We describe Keck-telescope spectrophotometry and imaging of the
companion of the "black widow" pulsar PSR J0952-0607, the fastest
known spinning neutron star (NS) in the disk of the Milky Way. The
companion is very faint at minimum brightness, presenting
observational challenges, but we have measured multicolor light curves
and obtained radial velocities over the illuminated "day" half of the
orbit. The model fits indicate system inclination
i=59.8°±1.9° and a pulsar mass MNS=2.35±0.17M☉,
the largest well-measured mass found to date. Modeling uncertainties
are small, since the heating is not extreme; the companion lies well
within its Roche lobe and a simple direct-heating model provides the
best fit. If the NS started at a typical pulsar birth mass, nearly
1M☉ has been accreted; this may be connected with the especially
low intrinsic dipole surface field, estimated at 6x107G. Joined with
reanalysis of other black widow and redback pulsars, we find that the
minimum value for the maximum NS mass is Mmax>2.19M☉
(2.09M☉) at 1σ (3σ) confidence. This is
∼0.15M☉ heavier than the lower limit on Mmax implied by the
white dwarf-pulsar binaries measured via radio Shapiro-delay
techniques.
Description:
Our observing campaign of PSR J0952-0607 uses the Keck-I 10m telescope
and the Low Resolution Imaging Spectrometer (LRIS). We report here on
two dual-color (typically g/i with a few r/i pairs) imaging runs and
six spectroscopy campaigns (spanning 2018-2022). Typical exposures
were 600-900s.
Objects:
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RA (ICRS) DE Designation(s)
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09 52 08.31 -06 07 23.4 PSR J0952-0607 = 4FGL J0952.1-0607
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
spectra.dat 43 72 *List of the reduced, cleaned FITS spectra for
PSR J0952-0607 and the comparison star over
six observing epochs (Data behind Figures 1-3)
sp/* . 144 Individual spectra in FITS format
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Note on spectra.dat: Connection with Figures:
For Figure 1 photometry was synthesized for the standard ugriz pass
bands using the IRAF script sbands, with the zeropoint of each
spectrum was set by correcting parallel sbands ugriz photometry of the
comparison star to the catalog magnitude (below). Note that additional
gray shifts are applied as described in the text.
For Figure 3 radial velocities were measured by cross-correlation with
a G1 standard star spectrum using the IRAF rvsao package. G1 cross
correlations of the comparison star were used to monitor spectrum to
spectrum and epoch to epoch shifts of zero velocity. See text.
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See also:
B/psr : ATNF Pulsar Catalogue (Manchester+, 2005)
J/ApJ/908/L46 : LC & radial velocities for PSRJ1810+1744 (Romani+, 2021)
Byte-by-byte Description of file: spectra.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- ID Spectrum ID
9- 15 F7.5 --- Phase [0.02/1] Binary phase of barycentered midpoint (1)
17- 29 A13 --- FileP Name of the FITS file in subdirectory "sp"
for J0952; column added by CDS
31- 43 A13 --- FileC Name of the FITS file in subdirectory "sp"
for the comparison star; column added by CDS
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Note (1): The orbital phases of each spectrum, as computed from the
barycentered time of the mid point and the ephemeris of
Nieder+ 2019ApJ...883...42N 2019ApJ...883...42N
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 11-Feb-2025