Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.naic.edu/vscience/schedule/2013Spring/DenevatagP2649.pdf Дата изменения: Tue Sep 11 04:14:21 2012 Дата индексирования: Mon Apr 11 16:44:05 2016 Кодировка: Поисковые слова: comet

Proposal Identification No.:

P2782 Arecibo Observatory

Date Received: 2012-Sep-04 17:09:02 William E. Gordon Telescope Observing Time Request COVER SHEET

Section I - General Information
Submitted for Sep 1 2012. This proposal has been submitted before. The previous proposal number is p2649. Proposal Type: General Category: Observation Category: Time Requested this semester: Hours Next Semester: Hours already used for this pro ject: Additional Hours required to complete pro ject: Minimum Useful Time: Expected Data Storage: Prop osal Title: ABSTRACT: Regular Pulsars Galactic 18 18 35.25 1 hour less than 100 GB

Measuring Two Neutron-Star Masses Using Shapiro Delay

Very recently, Demorest et al. (2010, Nature, 467, 1081) measured a pulsar mass of 1.97 +/- 0.04 solar masses, thereby greatly extending the known range of precisely measured neutron-star masses, and significantly constraining the equation of state for supra-nuclear-density matter. This ma jor result further emphasizes the questions of (i) how high a neutron-star mass can be?and (ii) what is the true distribution of neutron-star masses?Only through additional, new neutron-star mass measurements can these fundamental questions be answered, but opportunities for this are rare. Here we request 36 hours of Arecibo time in order to improve the Shapiro delay and mass measurements of the components in one PALFA-discovered binary system and try to detect the Shapiro delay in another. Outreach Abstract: Pulsar are very small, dense, and fast-rotating stars that behave like radio light houses, emitting a pulse of radio waves on each rotation. The intervals between successive pulses are almost exactly the same, similar to the ticks of a clock. If a radio "tick" from a pulsar arrives later than expected, it is often because the pulsar is in a binary system with another star, and the pulse has to pass near that star before it reaches the Earth. According to Einstein's theory of relativity, massive ob jects deform spacetime­in other words, time passes at a different rate depending on how close you are to a star. When a pulsar's radio pulses experience a delay from their expected arrival time at Earth, that delay depends on the mass of the pulsar and the mass of the other star in the binary system. By measuring this delay using the Arecibo telescope, we can essentially weigh both stars very precisely. This pro ject proposes to weigh both stars in two such binary systems.

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Name Julia Deneva Patrick Lazarus

Institution Arecibo Observatory Max-Planck-Institut fur Radioastronomie

E-mail deneva@naic.edu plazarus@mpifr-bonn.mpg.de

Phone 787-878-2612, ext. 315 +49 228 525 181

Student no G

Additional Authors
Paulo Freire (MPIfR), pfreire@mpifr-bonn.mpg.de

This work is part of a PhD thesis.

Remote Observing Request

Observer will travel to AO X Remote Observing In Absentia (instructions to operator)

Section I I - Time Request
The following times are in LST. For these observations night-time is not needed.

Begin ­ End Interval­Interval 18:30 ­ 20:00 ­ ­ ­

Days Needed at This Interval 12

Time Constraints (Must Be Justified in the Prop osal Text) Two sessions monthly. One should be on a day when the primary ob ject in the proposal, 1949+3106, is visible from Arecibo during superior conjunction. The other session should be a day earlier or a day later, to catch the pulsar near inferior conjunction (it is in a 1.9-day binary). We have calculated times of superior conjunction via an online script: http://astro.cornell.edu/deneva/conv/conjunction.php

Next Semester Time Request
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Begin ­ End Interval­Interval 18:30 ­ 20:00 ­ ­ ­

Days Needed at This Interval 12

Time Constraints (Must Be Justified in the Prop osal Text) Two sessions monthly. One should be on a day when the primary ob ject in the proposal, 1949+3106, is visible from Arecibo during superior conjunction. The other session should be a day earlier or a day later, to catch the pulsar near inferior conjunction (it is in a 1.9-day binary). We have calculated times of superior conjunction via an online script: http://astro.cornell.edu/ deneva/conv/conjunction.php

Section I I I - Instruments Needed
L-wide Atmospheric Observation Instruments:

Sp ecial Equipment or setup:

none

Section IV - RFI Considerations Frequency Ranges Planned

This proposal requires Iridium RFI protection at 1612 MHz between 10pm and 6am EST. This proposal requires coordination with Punta Salinas radar within the band 1222-1381 MHz.. This proposal requires coordination with GPS L3 at 1381 MHz.

Section V - Observing List Target List
Colums: Name, RA, DEC, Rise(LST), Set(LST) J1949+3106 19:49:29.64 31:06:03.83 18:43:48 20:56:15 J1952+2630 19:52:36.84 26:30:28.04 18:35:31 21:10:49

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