Transitional
Millisecond Pulsars
Jason Hessels
(ASTRON/U. of Amsterdam)
MPIfR/AIfA - Bonn - 18/05/15
Acknowledgements
Lots of wavebands, lots of telescopes,
lots of collaborators
• Diego Altamirano
• Anne Archibald
• Cees Bassa
• Slavko Bogdanov
• Rene Breton
• Caroline D’Angelo
• Adam Deller
• George Heald
• Craig Heinke
• Gemma Janssen
• Amruta Jaodand
• Vicky Kaspi
• Christian Knigge
• Andrew Lyne
• James Miller-Jones
• Javi Moldon
• Zsolt Paragi
• Alessandro Papitto
• Ale Patruno
• Brian Prager
• Scott Ransom
• Ben Stappers
• Thomas Tauris
• Shriharsh Tendulkar
• Rudy Wijnands
Telescopes/Instruments
Lots of wavebands, lots of telescopes
Radio: Arecibo, EVN, GBT, LOFAR, Lovell,
VLA, Westerbork
Optical: Gemini,VLT/X-Shooter/FORS2,
Hubble
X-ray: Chandra, XMM-Newton, Swift,
NuSTAR
Gamma-ray: Fermi,VERITAS
Pulsar Recycling
Saxton, NRAO
LMXB (some IMXB)
Radio (some also g-ray)
Alpar, Cheng, Ruderman & Shaham1982
Rhadakrishnan & Srinivasan 1982
Pulsar Recycling
For Myrs - Gyrs?
Saxton, NRAO
LMXB (some IMXB)
Radio (some also g-ray)
Alpar, Cheng, Ruderman & Shaham1982
Rhadakrishnan & Srinivasan 1982
Transitional
Millisecond Pulsars
(tMSPs)
• 3 (+1) known.
• First 3 seen as a radio MSP and
as an accreting NS-LMXB.
• Two have shown coherent
pulsations at ~1034 erg/s.
• One has gone into a full AMXP
outburst at ~1036 erg/s.
Are all black widows and redbacks capable
of being tMSPs?
See e.g. Archibald et al. 2009; Papitto et al. 2013; Stappers et al. 2014; Bassa et al. 2014
The tMSPs at a Glance
• PSR J1023+0038: currently accreting; was a
radio MSP until summer 2013.
• XSS J12270-4859: currently a radio pulsar;
was a qLMXB until end 2012.
• M28I: currently a radio pulsar; showed a
typical AMXP outburst in spring 2013.
• 1RXS J154439.4-112820: very similar optical,
X-ray, gamma-ray properties. Radio pulsar state
not yet seen. (see Bogdanov & Halpern 2015)
Related to AMXPs, qLMXBs, and VFXBs?
So far all 3(+1) are redback MSPs
See e.g. Archibald et al. 2009; Papitto et al. 2013; Stappers et al. 2014; Bassa et al. 2014
Radio
Pulsar State
Intermediate
Disc State
• Observed radio/gamma-
• No visible radio pulsar (off?).
• Increased optical, X-ray, and
ray pulsar.
• Likely radio eclipses.
• Lots of orbital timing
noise.
• Modulation of X-rays at
orbital period (shock).
gamma-ray brightness.
• Double peaked optical
emission lines.
• Flat-spectrum radio
continuum source (jet?).
• No X-ray orbital modulation.
• X-ray dropouts and flares.
Transitional
Millisecond Pulsars
(tMSPs)
States
Outburst (Lx > 1036 erg/s)
Modes
High?
Low?
Typical AMXP
Intermediate (Lx ~ 1033-34 erg/s)
Accretion disc; intermittent X-ray pulsations
Radio Pulsar (Lx ~ 1032 erg/s)
Accretion disc cleared? No Roche-lobe overflow
Flare
High
Low
Unobscured
Eclipsed
See e.g. Archibald et al. 2009; Papitto et al. 2013; Stappers et al. 2014; Bassa et al. 2014
PSR J1023+0038: a
`missing link’
Accretion disk present
Radio millisecond pulsar
circa 2000
circa 2008
PSR J1023+0038’s halcyon
days as a radio ms-pulsar
• From 2008 - 2013, PSR
J1023+0038 was regularly
detected with Arecibo,
GBT, Lovell, Westerbork.
• Long-term timing shows
significant orbital
modulation.
Archibald et al. 2013
PSR J1023+0038 Vanishes
• In June 2013 the radio
Poof!
Patruno et al. 2014
Stappers et al. 2014
Tendulkar et al. 2014
pulsar suddenly became
undetectable.
• Even 5GHz Arecibo
observations found no signal.
• `Turn-off’ constrained to a
~2-week period.
• Associated optical, X-ray,
and gamma-ray brightening.
• Optical spectrum shows
accretion disk is back.
• A `change of state’.
PSR J1023+0038: gamma-ray
brightening
Radio
detections
o : radio pulse
detection
+ : radio pulse
non-detection
Eclipse
phases
Gamma-ray
lightcurve
Stappers et al. 2014
PSR J1023+0038: gamma-ray
brightening
Radio
detections
o : radio pulse
detection
+ : radio pulse
non-detection
Eclipse
phases
Gamma-ray
lightcurve
Stappers et al. 2014
Window of radio
disappearance and
state change
Disc state: Multi-wavelength
campaign
Bogdanov et al. 2015
Deller et al. 2015
Archibald et al. 2015
Telescopes used: Arecibo, GBT,
Westerbork, Lovell, XMM-Newton,
VLT, JVLA, Swift, HST, LOFAR
Disc state: JVLA
Observations
M28I
XSS J12270-4859
Miller-Jones
PSR J1023+0038
tMSPs seem to follow a parallel track to the BH-LMXBs
Radiatively inefficient accretion
Deller et al. 2015
Disc state: JVLA
Observations
1RXS J154439.4-112820
Assume d ~ 3kpc
M28I
1RXS J154439.4-112820
XSS J12270-4859
Miller-Jones
PSR J1023+0038
0.3-10keV =
3.5x10-12 erg/s/cm2
LX = 3.8 x 1033 erg/s
VLA & Swift
observations last week:
10GHz = 30 microJy
LR = 1.3 x 1027 erg/s
Jaodand, Deller, Hessels et
al. 2015, in prep.
Preliminary results suggest that
1RXS J154439.4-112820 also fits the trend!
XMM Obs 2014 Jun
XMM Obs 2013 Nov
PSR J1023+0038 “Moding”
2x 130ks with XMM-Newton
• Accreting state shows
three “modes”.
• Phenomenology is
remarkably stable of year
timescales.
• Same seen in other
tMSPs.
• Powerlaw spectrum, not
as hard as in radio MSP
state.
• Spectrum basically
identical in all modes.
Archibald et al. 2015
Bogdanov et al. 2015
50
1)
40
Rate (s
XMM Obs 2013 Nov
PSR J1023+0038 “Moding”
30
20
10
0
100
102
104
106
108
110
XMM Obs 2014 Jun
time since observation start (ks)
2x 130ks with XMM-Newton
Green = Low mode
Black = High mode
Red = Flare mode
Yellow = Soft proton flare
Archibald et al. 2015
Bogdanov et al. 2015
PSR J1023+0038 “Moding”
log10 number of 10-s bins
XMM Obs 2013 Nov
3.5
XMM Obs 2014 Jun
high
flare
3.0
2.5
2.0
1.5
1.0
Nov
June
0.5
0.0
2x 130ks with XMM-Newton
low
1.0
0.5
0.0
0.5
1.0
log10 count rate (s 1 )
1.5
2.0
Low mode ~ 15%
High mode ~ 80%
Flare mode ~ 5%
Archibald et al. 2015
Bogdanov et al. 2015
high
flare
low
Count rate (s
1)
8
6
4
2
0.025
0.020
0.015
0.010
0.005
0.000
0
RMS pulsed fraction (%)
8
1.10
0.11
0.10
1.05
1.00
0.95
0.90
0.5
Nov
June
0.030
1)
10
0.12
0.09
0.4
0.2
0.0
0.2
0.4
0.6
0.0
0.035
12
RMS pulsed flux (s
4.8
LMXB state
4.6
4.4
4.2
4.0
3.8
3.6
0.06
0.04
0.02
0.00
0.02
0.04
0.06
RMSP state
0.13
Fractional count rate
Count rate
Count rate
di↵erence (s 1 ) (0.3–2.5 keV; s
1)
Count rate
di↵erence (s 1 )
Count rate
(0.3–10 keV; s
1)
PSR J1023+0038 Pulsations
1.0
1.5
2.0
Rotational phase
Disc vs. radio MSP pulsations
0.85
0.0
7
6
5
4
3
2
1
0
0.5
1.0
1.5
2.0
Phase
Pulsations only in high mode!
100
101
Energy (keV)
Spectra
Situation is basically identical over timescale of ~year
Archibald et al. 2015
PSR J1023+0038 as an AMXP
10
8
10
9
1037 erg s
1035 erg s
1
• PSR J1023+0038 looks
like a typical AMXP in
outburst.
• BUT it is 100x fainter
and persistent for > 1.5
years.
• Do other AMXPs do
this?
• Remember that PSR
J1023+0038 is at 1.3kpc.
• Cen X-4 apparently
doesn’t do this.
1
10
10
10
11
PSR J1023+0038
1033 erg s
1
flux (erg s
1
cm
2)
M28I
10
12
Cen X-4
10
13
1031 erg s
10
14
10
15
10
16
1
100
101
d (kpc)
Archibald et al. 2015
PSR J1023+0038 Pulsations
10
Year
2009 2010 2011 2012 2013 2014 2015 2016
Tasc (s)
0
10
Dense campaign of 4 x 20ks
(Nov/Dec 2014)
20
30
40
radio
X-ray
Detrended
Tasc (s)
20
• Can track spin behaviour
during intermediate accreting
state.
• Is the pulsar spinning-up/
down?
15
10
5
0
5
10
54500 55000 55500 56000 56500 57000 57500
Modified Julian Date (MJD)
Archibald et al. 2015 + new XMM-Newton campaign
Is PSR J1023+0038 Spinning-up
or down?
• Campaign of 4
additional XMM
observations.
• Spaced logarithmically
over 20 days.
• Fit for Tasc shift and then
fold.
Preliminary: Ṗacc = 1.03 +/- 0.03 Ṗradio
(i.e. Ṗacc ~ Ṗradio)
Jaodand, Archibald, Hessels et al. 2015, in prep.
Open Questions
• How do we really produce the observed population
of radio millisecond pulsars?
• What causes the state transitions?
• Do such sources transition back and forth for Gyrs?
• What causes the gamma-ray brightening?
• Are we seeing propeller-mode accretion?
• Are other variable Fermi gamma-ray sources also
transitional millisecond pulsars?
• Can we find a sub-MSP in such a system?
• What X-ray source classes are related?
Related Bibliography
(Abridged and biased to my own work mostly)
Archibald et al. 2009 - LMXB/MSP missing link
Bogdanov et al. 2011 - X-ray orbital modulation shows intra-binary shock
Hessels et al. 2011 - GBT discovery of MSP spiders assoc. with Fermi UnIDs
Deller et al. 2012 - Parallax distance for PSR J1023+0038
Breton et al. 2013 - Optical companion and modeling of light curves
Papitto et al. 2013 - M28I switches between rotation and accretion power
Archibald et al. 2013 - Long-term timing of PSR J1023+0038 in radio
Gentile et al. 2014 - Orbital modulation of X-rays in MSP spiders
Patruno et al. 2014 - New accretion disk in PSR J1023+0038 system
Stappers et al. 2014 - PSR J1023+0038 radio MSP disappears; gamma-rays brighten 5x
Tendulkar et al. 2014 - No hard X-ray cutoff with NUSTAR
Bassa et al. 2014 - XSS J12270-4859 is also a tMSP
Bogdanov et al. 2014 - XSS J12270-4859 shows X-ray orbital modulation
Bogdanov et al. 2015 - Detailed X-ray/opt./radio phenomenology of PSR J1023+0038
Deller et al. 2015 - PSR J1023+0038 has a surprisingly bright jet/outflow
Archibald et al. 2015 - PSR J1023+0038 shows coherent X-ray pulsations
Roy et al. 2015 - XSS J12270-4859 is a radio MSP: PSR J1227-4859
Papitto et al. 2015 - XSS J12270-4859 shows coherent X-ray pulsations