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Proposal Identication No.: P1733 Date Received: 2003-Oct-01 13:36:35
Technical Page
Proposal Type: Regular
General Category: Pulsars
Observation Category: Galactic
Total Time Requested: 13.5 Hours
Proposal Title: High frequency search for pulsation from the Soft X-ray transient Aql X-1 in
quiescence
ABSTRACT:
We plan to search coherent radio emission from the neutron star in the soft X-ray transient Aql X-1 during its
quiescent state. Observational evidence like the presence of a hard X-ray energy tail or a non-disk like optical
Doppler tomography, as well as theoretical evolutionary considerations, suggest the presence of anactive
millisecond radio pulsar in these systems (with a spin frequency of 549 Hz, as inferred from coherent pulsations
during X-ray type I bursts). Previous investigations carried out at Parkes gave negative results, but were carried
out at low frequencies, for which absorption can strongly hamper the detection. The large collecting area of the
Arecibo radiotelescope, combined with the large bandwidth oered by the use of 4 WAPPs, provides the
opportunity of searching radiopulses at high frequencies (5, 6 and 8 GHz, at which we get rid of the free-free
absorption), while preserving enough sensitivity (>20 better than the 70-m radiotelescope class) for
counterbalancing the expected spectral decline of the source.
Name Institution E-mail Phone Student
Sergio Campana INAF-Osservatorio
astronomico di Brera
campana@merate.mi.astro.it +39-039-
999111
no
Service Observing Request Remot e Observing Request
X None X No
All of the observing run. Maybe
Part of the observing run. Yes
Queue Observing
Instrument Setup
C X-high
Atmospheric Observation Instruments:
Special Equipment or setup: We will use 4 WAPP for a total band of 400 MHz.
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RFI Considerations
Frequency Ranges Planned
4800-5200
5600-6000
8000-8400
2