Einstein@Home Gamma-ray Pulsar Discoveries in Fermi-LAT Data

Info

Einstein@Home searches data from NASA's Fermi Gamma-ray Space Telescope for signals from gamma-ray pulsars. Pulsars are very compact stars with extreme physical properties compared to normal matter. They are rapidly spinning neutron stars that emit pulses, observable from radio to gamma-ray wavelengths.

Searching for new pulsars is an enormous computational challenge, because their spin frequencies, sky position and other parameters are unknown in advance. Hence this is called a "blind" search, where one explicitly searches over a dense grid in parameter space. However, the number of discrete grid points to cover such multi-dimensional parameter spaces is tremendous and renders "brute forces approaches" computationally unfeasible.

We have developed novel and much more efficient data-analysis methods for the volunteer supercomputer Einstein@Home, which ranks among the fastest 25 computer systems worldwide. Einstein@Home has enabled the discoveries of new gamma-ray pulsars that were previously inaccessible on computational grounds.

These gamma-ray pulsar discoveries provide important contributions to advance our (yet very poor) understanding these stellar objects, their population, and their role in our Universe.


The Einstein@Home searches for new gamma-ray pulsars

In 2014, we began the 4th Einstein@Home survey for gamma-ray pulsars, or "FGRP4". This survey incorporated many new advances that we learned during our previous searches and investigation of blind search methods. In addition, we were able to utilised the superior "Pass 8" data from the Fermi-LAT team, and search in longer data sets than ever before. In combination, these improvements led to FGRP4 being our most sensitive survey to date.

We are very pleased to be able to announce the first set of results from FGRP4. Including the discovery of PSR J1906+0722 at the beginning of this survey, these bring the total number of gamma-ray pulsars discovered by our Einstein@Home volunteers to 19. You can find the details and plots of all the new discoveries below!

Currently we are working very hard to study all of the results from FGRP4, and we are hoping to present these in a series of papers in the near future.

As always, we are extremely grateful to all of our volunteers, especially those whose computers contributed to these new discoveries. To say "we couldn't have done it without you!" would be a terrible understatement!

Timeline

The above plot illustrates the number of gamma-ray pulsars discovered in blind searches using NASA's Fermi Gamma-ray Space Telescope as a function of time (when the discoveries were published). Since the Fermi satellite was launched in 2008, it has been continuously scanning the entire sky and thus is providing an ever increasing data set. In principle, having more data available allows us to do more sensitive pulsar searches. However, at the same time, the computational cost also increases rapidly with the longer data time spans. Thus, as the graphic shows, over the last few years the only new such discoveries were made with Einstein@Home, thanks to the massive collective computing power provided by the Einstein@Home volunteers.


The discoveries made by Einstein@Home volunteers in detail

Below we list for each pulsar the volunteers whose computers discovered the pulsar, and the date at which the pulsar was found.

We also provide a list of selected characteristics for each of the pulsars. Right ascension is one of the two celestial coordinates that specify the sky position of the pulsar. Declination is the second of these. The spin frequency describes how many time per second the pulsar is rotating. The first frequency derivative describes how much the pulsar is slowing down over time. The energy required to emit electromagnetic radiation is drawn from the pulsar rotation. The characteristic age is a rough estimate of the pulsar's age, computed from the spin frequency and its derivative. Finally, the spin-down power is a measure of the total energy emitted by the pulsar. For comparison, our Sun outputs roughly 4 x 1033 erg per second. All pulsars below have a much higher spin-down power.

The graphics on the right show the pulse profile of each pulsar in green, and the phase-folded arrival times of all the gamma-ray photons on the far right. These plots require precise knowledge of the pulsar sky position, its spin frequency, and spin frequency derivative. Using these, each photon can be assigned a rotational phase, i.e., in which direction the pulsar was pointing when the gamma-ray photon was emitted. Thus, we can reconstruct the gamma-ray emission as a function of pulsar rotation phase and resolve the pulse profile.



Pulsar J0002+6216

J0002 J0002
Volunteers (Country):
UW-Madison CAE (USA) and RUElwell (USA)

Date:
31 Dec 2014

Survey:
FGRP4

Selected pulsar parameters:
Right ascension: 00:02
Declination: +62:16
Spin frequency: 8.67 Hz
First frequency derivate: -4.48 x 10-13 Hz/s
Characteristic age: 306.3 kyrs
Spin-down power: 1.5 x 1035 erg/s


Pulsar J0359+5414

J0359 J0359
Volunteers (Country):
Whelton Miller (USA), ATLAS AEI Hannover (Germany) and Delty (USA)

Date:
15 Dec 2014

Survey:
FGRP4

Selected pulsar parameters:
Right ascension: 03:59
Declination: +54:14
Spin frequency: 12.59 Hz
First frequency derivate: -2.65 x 10-12 Hz/s
Characteristic age: 75.2 kyrs
Spin-down power: 1.3 x 1036 erg/s


Pulsar J0554+3107

J0554 J0554
Volunteers (Country):
David Z (Canada) and Test (France)

Date:
06 Jan 2012

Survey:
FGRP1

Selected pulsar parameters:
Right ascension: 05:54:05.01(3)
Declination: +31:07:41(4)
Spin frequency: 2.15 Hz
First frequency derivate: -0.66 x 10-12 Hz/s
Characteristic age: 51.7 kyrs
Spin-down power: 5.6 x 1034 erg/s


Pulsar J0631+0646

J0631 J0631
Volunteers (Country):
KataJun (Japan) and huwar

Date:
20 Jan 2015

Survey:
FGRP4

Selected pulsar parameters:
Right ascension: 06:31
Declination: +06:46
Spin frequency: 9.01 Hz
First frequency derivate: -2.94 x 10-13 Hz/s
Characteristic age: 486.1 kyrs
Spin-down power: 1.0 x 1035 erg/s


Pulsar J1057-5851

J1057 J1057
Volunteers (Country):
Syracuse University (USA) and LLO_LDAS (USA)

Date:
28 Oct 2014

Survey:
FGRP4

Selected pulsar parameters:
Right ascension: 10:57
Declination: -58:51
Spin frequency: 1.61 Hz
First frequency derivate: -2.61 x 10-13 Hz/s
Characteristic age: 97.7 kyrs
Spin-down power: 1.7 x 1034 erg/s


Pulsar J1105-6037

J1105 J1105
Volunteers (Country):
ATLAS AEI Hannover (Germany) and Syracuse University (USA)

Date:
03 Oct 2014

Survey:
FGRP4

Selected pulsar parameters:
Right ascension: 11:05
Declination: -60:37
Spin frequency: 5.13 Hz
First frequency derivate: -5.75 x 10-13 Hz/s
Characteristic age: 141.4 kyrs
Spin-down power: 1.2 x 1035 erg/s


Pulsar J1208-6238

J1208 J1208
Volunteers (Country):
UW-Madison CAE (USA) and UH RCC - Maxwell (USA)

Date:
03 Oct 2014

Survey:
FGRP4

Selected pulsar parameters:
Right ascension: 12:08:13.96(6)
Declination: -62:38:02.3(4)
Spin frequency: 2.27 Hz
First frequency derivate: -1.68 x 10-11 Hz/s
Characteristic age: 2,700 yrs
Spin-down power: 1.5 x 1036 erg/s


Pulsar J1350-6225

J1350 J1350
Volunteers (Country):
PeRu (Czech Republic) and Bryden Kanngiesser (Canada)

Date:
19 Jun 2015

Survey:
FGRP4

Selected pulsar parameters:
Right ascension: 13:50
Declination: -62:25
Spin frequency: 7.24 Hz
First frequency derivate: -4.65 x 10-13 Hz/s
Characteristic age: 246.4 kyrs
Spin-down power: 1.3 x 1035 erg/s


Pulsar J1422-6138

J1422 J1422
Volunteers (Country):
Mak-ino (Japan) and Thomas M. Jackson (USA)

Date:
14 Dec 2011

Survey:
FGRP1

Selected pulsar parameters:
Right ascension: 14:22:27.07(1)
Declination: -61:38:28(1)
Spin frequency: 2.93 Hz
First frequency derivate: -0.83 x 10-12 Hz/s
Characteristic age: 55.8 kyrs
Spin-down power: 9.6 x 1034 erg/s


Pulsar J1522-5735

J1522 J1522
Volunteers (Country):
The NEMO computing cluster (USA) and Chen (USA)

Date:
30 Sep 2011

Survey:
FGRP1

Selected pulsar parameters:
Right ascension: 15:22:05.3(1)
Declination: -57:35:00(1)
Spin frequency: 9.79 Hz
First frequency derivate: -2.99 x 10-12 Hz/s
Characteristic age: 51.8 kyrs
Spin-down power: 115.7 x 1034 erg/s


Pulsar J1528-5838

J1528 J1528
Volunteers (Country):
fred c (USA) and Gabriel Vasquez

Date:
25 Mar 2015

Survey:
FGRP4

Selected pulsar parameters:
Right ascension: 15:28
Declination: -58:38
Spin frequency: 2.81 Hz
First frequency derivate: -1.96 x 10-13 Hz/s
Characteristic age: 227.6 kyrs
Spin-down power: 2.2 x 1034 erg/s


Pulsar J1623-5005

J1623 J1623
Volunteers (Country):
r4p and Greg Dorais (USA)

Date:
04 Oct 2014

Survey:
FGRP4

Selected pulsar parameters:
Right ascension: 16:23
Declination: -50:05
Spin frequency: 11.75 Hz
First frequency derivate: -5.75 x 10-13 Hz/s
Characteristic age: 323.9 kyrs
Spin-down power: 2.7 x 1035 erg/s


Pulsar J1624-4041

J1624 J1624
Volunteers (Country):
xio.nyc (Antarctica) and Hung Tran (USA)

Date:
20 Dec 2014

Survey:
FGRP4

Selected pulsar parameters:
Right ascension: 16:24
Declination: -40:41
Spin frequency: 5.96 Hz
First frequency derivate: -1.68 x 10-13 Hz/s
Characteristic age: 562.9 kyrs
Spin-down power: 3.9 x 1034 erg/s


Pulsar J1650-4601

J1650 J1650
Volunteers (Country):
Syracuse University (USA) and Eric Schwartz (USA)

Date:
17 Oct 2014

Survey:
FGRP4

Selected pulsar parameters:
Right ascension: 16:50
Declination: -46:01
Spin frequency: 7.87 Hz
First frequency derivate: -9.37 x 10-13 Hz/s
Characteristic age: 133.0 kyrs
Spin-down power: 2.9 x 1035 erg/s


Pulsar J1827-1446

J1827 J1827
Volunteers (Country):
ATLAS AEI Hannover (Germany) and LLO_LDAS (USA)

Date:
19 Dec 2014

Survey:
FGRP4

Selected pulsar parameters:
Right ascension: 18:27
Declination: -14:46
Spin frequency: 2.00 Hz
First frequency derivate: -1.82 x 10-13 Hz/s
Characteristic age: 174.5 kyrs
Spin-down power: 1.4 x 1034 erg/s


Pulsar J1844-0346

J1844 J1844
Volunteers (Country):
Aurelien FAUCHEUX (France) and Roger (USA)

Date:
18 Nov 2014

Survey:
FGRP4

Selected pulsar parameters:
Right ascension: 18:44
Declination: -03:46
Spin frequency: 8.86 Hz
First frequency derivate: -1.21 x 10-11 Hz/s
Characteristic age: 11.6 kyrs
Spin-down power: 4.2 x 1036 erg/s


Pulsar J1906+0722

J1906 J1906
Volunteers (Country):
Connor Barry (USA) and Richard Johnson (USA)

Date:
11 Sep 2014

Survey:
FGRP4

Selected pulsar parameters:
Right ascension: 19:06:31.20(1)
Declination: +07:22:55.8(4)
Spin frequency: 8.97 Hz
First frequency derivate: -2.88 x 10-12 Hz/s
Characteristic age: 49.2 kyrs
Spin-down power: 1.02 x 1036 erg/s


Pulsar J1932+1916

J1932 J1932
Volunteers (Country):
Doug Lean (Australia) and Hans-Peter Tobler (Germany)

Date:
19 Sep 2011

Survey:
FGRP1

Selected pulsar parameters:
Right ascension: 19:32:19.70(4)
Declination: +19:16:39(1)
Spin frequency: 4.80 Hz
First frequency derivate: -2.15 x 10-12 Hz/s
Characteristic age: 35.4 kyrs
Spin-down power: 40.7 x 1034 erg/s


Pulsar J2017+3625

J2017 J2017
Volunteers (Country):
gramoll (USA) and Rogir (Germany)

Date:
09 Sep 2014

Survey:
FGRP4

Selected pulsar parameters:
Right ascension: 20:17
Declination: +36:25
Spin frequency: 6.00 Hz
First frequency derivate: -4.89 x 10-14 Hz/s
Characteristic age: 1942.8 kyrs
Spin-down power: 1.2 x 1034 erg/s



Einstein@Home
Colin J. Clark (Last Update: Nov 17, 2016)