J/ApJ/769/108 Optical photometry of 4 millisecond pulsars (Breton+, 2013)
Discovery of the optical counterparts to four energetic Fermi millisecond
pulsars.
Breton R.P., van Kerkwijk M.H., Roberts M.S.E., Hessels J.W.T., Camilo F.,
McLaughlin M.A., Ransom S.M., Ray P.S., Stairs I.H.
<Astrophys. J., 769, 108 (2013)>
=2013ApJ...769..108B 2013ApJ...769..108B
ADC_Keywords: Pulsars ; Photometry, ugriz ; Gamma rays
Keywords: binaries: general; pulsars: general;
pulsars: individual (PSR J1810+1744, PSR J0023+0923, PSR J2215+5135,
PSR J2256-1024, PSR B1920+57, PSR J1023+0038)
Abstract:
In the last few years, over 43 millisecond radio pulsars have been
discovered by targeted searches of unidentified γ-ray sources
found by the Fermi Gamma-Ray Space Telescope. A large fraction of
these millisecond pulsars are in compact binaries with low-mass
companions. These systems often show eclipses of the pulsar signal and
are commonly known as black widows and redbacks because the pulsar is
gradually destroying its companion. In this paper, we report on the
optical discovery of four strongly irradiated millisecond pulsar
companions. All four sources show modulations of their color and
luminosity at the known orbital periods from radio timing. Light curve
modeling of our exploratory data shows that the equilibrium
temperature reached on the companion's dayside with respect to their
nightside is consistent with about 10%-30% of the available spin-down
energy from the pulsar being reprocessed to increase the companion's
dayside temperature. This value compares well with the range observed
in other irradiated pulsar binaries and offers insights about the
energetics of the pulsar wind and the production of γ-ray
emission. In addition, this provides a simple way of estimating the
brightness of irradiated pulsar companions given the pulsar spin-down
luminosity. Our analysis also suggests that two of the four new
irradiated pulsar companions are only partially filling their Roche
lobe. Some of these sources are relatively bright and represent good
targets for spectroscopic follow-up.
Description:
We were awarded 7.67hr on Gemini North (program GN-2010B-Q-77) to
search for the counterparts of four energetic binary millisecond
pulsars (MSPs) with the GMOS-N instrument: PSRs J1810+1744,
J0023+0923, J2215+5135, and J2256-1024.
Our observing strategy consisted of collecting data at four different
epochs, with each observing session consisting of a 320s i-band, 620s
g-band, and 320s i-band exposure sequence.
The field of PSR J2215+5135 was also serendipitously observed by the
UVOT instrument on board Swift while it was monitoring a nearby
gamma-ray burst. We also obtained some exploratory exposures during an
observing run at the NTT using the tri-band ULTRACAM imager and
managed to obtain an additional z-band and g-band images for
PSR J2256-1024.
Our complete photometric results for the pulsar companions are
available in Tables 2-5, as well as for a set of comparison field
stars in Table 6.
Objects:
----------------------------------------------------------------------
RA (2000) DE Designation(s) (Table)
----------------------------------------------------------------------
00 23 16.89 +09 23 24.18 PSR J0023+09 = 2FGL J0023.5+0924 (table2)
18 10 37.28 +17 44 37.38 PSR J1810+17 = PSR J1810+1744 (table3)
22 15 32.68 +51 35 36.45 PSR J2215+51 = 2FGL J2215.7+5135 (table4)
22 56 56.39 -10 24 34.37 PSR J2256-10 = PSR J2256-1024 (table5)
----------------------------------------------------------------------
*: Positions derived from optical astrometry. Uncertainties are
dominated by the catalog systematics of 0.07" in UCAC3 (J0023+0923,
J1810+1744, and J2215+5135) and 0.1" in SDSS DR7 (J2256-1024).
See table 1.
----------------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 53 10 Photometry of PSR J0023+09
table3.dat 53 14 Photometry of PSR J2256-10
table4.dat 53 12 Photometry of PSR J1810+17
table5.dat 53 15 Photometry of PSR J2215+51
table6.dat 89 256 Photometry of four fields
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See also:
B/eso : ESO Science Archive Catalog (ESO, 1991-2014)
J/ApJ/763/80 : GBT 350MHz survey. I. 13 new pulsars (Boyles+, 2013)
J/ApJS/208/17 : 2nd Fermi LAT cat. of gamma-ray pulsars (2PC) (Abdo+, 2013)
J/ApJS/199/31 : Fermi LAT second source catalog (2FGL) (Nolan+, 2012)
J/ApJ/753/83 : Associations to 1FGL sources (Ackermann+, 2012)
J/AZh/79/501 : Radio luminosities of normal + millisecond PSRs (Kuz'min, 2002)
Byte-by-byte Description of file: table[2345].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- Band GMOS band (g, i or uvw1)
6 A1 --- Inst Instrument (GMOS if blanck, ULTRACAM if "U",
UVOT if "S")
8- 19 F12.6 d MJD Time
21- 26 F6.4 --- Phase Orbital phase (1)
28- 34 F7.3 uJy Flux [-1.4/103] Flux in Band
36- 40 F5.3 uJy e_Flux [0.02/6] Flux uncertainty (G1)
42- 47 F6.3 mag mag [18.8/27.5] Magnitude in Band (G2)
49- 53 F5.3 mag e_mag [0.003/0.8] mag uncertainty (G1)
--------------------------------------------------------------------------------
Note (1): Orbital phases are measured from the companion's inferior conjunction.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- --- [PSR]
5- 12 A8 --- PSR Field identifier
14- 21 F8.4 deg RAdeg Right Ascension in decimal degrees (J2000)
23- 31 F9.5 deg DEdeg Declination in decimal degrees (J2000)
33- 39 F7.3 uJy Fg The g band flux density
41- 45 F5.3 uJy e_Fg Uncertainty in Fg (G1)
47- 53 F7.3 uJy Fi The i band flux density
55- 61 F7.3 uJy e_Fi Uncertainty in Fi (G1)
63- 69 F7.4 mag gmag The g band magnitude (AB scale) (G2)
71- 76 F6.4 mag e_gmag Uncertainty in gmag (G1)
78- 83 F6.3 mag imag The i band magnitude (AB scale) (G2)
85- 89 F5.3 mag e_imag Uncertainty in imag (G1)
--------------------------------------------------------------------------------
Global notes:
Note (G1): The flux and magnitude errors represent the formal uncertainties.
One should also add in quadrature the zeropoint calibration errors:
-----------------------------
Field g-band i-band
-----------------------------
PSR J0023+09 0.319 0.757
PSR J2256-10 0.104 0.119
PSR J1810+17 0.301 0.308
PSR J2215+51 0.302 0.302
-------------------------------
Note (G2): AB magnitudes in the Lupton system,
m=m0-2.5logb'-(2.5loge)sinh-1 (f/2b'), using a zero point
m0=-48.6 and softening parameters:
-----------------------------
Field g-band i-band
(uJy)
-----------------------------
PSR J0023+09 0.059 0.233
PSR J2256-10 0.025 0.064
PSR J1810+17 0.051 0.099
PSR J2215+51 0.242 0.462
-----------------------------
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 15-Dec-2014