Search for bursty and pulsed radio emission from XDINSs

XDINSs stand for X-ray Dim Isolated Neutron Stars. To date, a total of seven such sources are known, all discovered in ROSAT All-Sky Survey [Voges et al. 1999] They are also sometimes called the "Magnificent Seven" (or M7). They share very similar properties such as: soft X-ray BB-like spectrum, kT ~ 40-100 eV very faint optical counterparts, fX/fV > 104 ∴ isolated NS high proper motion ∴ nearby low hydrogen column density, nH ~ 1020 cm-2 ∴ close-by (parallaxes are measured for 2 XDINSs as well) ∴ low-luminosity ~ 1031 erg s-1 (dim) no evidence for a binary companion, or an associated SNR long spin periods, P ~ 3-12 s for all of them no found radio emission so far For a recent review see h+07, k+08. The aim of this project is to search for pulses and bursty radio emission from XDINSs to limk them in their evolutionary scenarios with other classes of neutron stars, such as magnetars and RRATs. They occypy similar, but not identical, regions in the P-Pdot diagram with ages and magnetic fields suggesting evolutionary relationships.

Collaborators:

• Maura McLaughlin (WVU, Department of Physics)
• Duncan Lorimer (WVU, Department of Physics)
• Marta Burgay (INAF – Osservatorio Astronomico di Cagliari)
• Andrea Possenti (INAF – Osservatorio Astronomico di Cagliari)
• Roberto Turolla (University of Padua)
• Sergei Popov (Sternberg Astronomical Institute)
• Silvia Zane (Mullard Space Science Laboratory)

Observations

Observations of six out of seven known XDINSs were carried out with the Robert C. Byrd Green Bank Radio Telescope at a center frequency of 820 MHz. The list of observed sources is presented in the Table below with measured values of P, dP/dt from X-ray observations. References for corresponding papers are also given.

XDINS	P	dP/dt	d	Ref
	(s)	(10-12s s-1)	(kpc)
RX J0720.4–3125	8.39	0.0698	0.36	hmb+97, kvk+05
RX J0806.4–4123	11.37	< 2		hz+02, hmz+04
RX J1308.6+2127	10.31	0.112		hsh+03, kvk+05
RX J1605.3+3249	6.88 ?	—		h+07
RX J1856.5–3754	7.055	0.0297	0.161	tm+07, vkk+08
RX J2143.0+0654	9.437	0.04		zct+05, kvk+09

Fast Folding Algorithm (FFA):

• Background: Staelin, 1969
• Implementation: ffasearch [Please, give a link to this page and cite the paper Kondratiev et al., 2009, if you are going to use it. Thanks!]
• Comparison: FFA versus FFT

Results:

• Single-Pulse Search
• FFA search

Talks, publications:

• NRAO Postdoctoral Symposium, 2007 [ppt]
• "40 Years of Pulsars: Millisecond Pulsars, Magnetars and More", held at McGill University, Montreal, Canada on August 12-17, 2007 [poster] [proceedings]
• Talk at Pulsar Group Meeting at Epping, ATNF on February, 2008 [pdf]
• Kondratiev et al., "New Limits on Radio Emission from X-ray Dim Isolated Neutron Stars", 2009, ApJ, accepted, arXiv:0907.0054

---

Last Modified: