The central regions of the Galaxy

Particular globular cluster pulsars of interest

PSR B1620-26 is within the globular cluster M4. This pulsar system contains planetary mass bodies.

Determining the population of globular cluster pulsars

Turk & Lorimer (2013) described a Bayesian method that can be applied to studying the pulsar population in a globular cluster. The number of pulsars in any given cluster depends upon the parameters of the globular cluster. In particular Hui et al. (2010) proposed a relationship between the pulsar abundance in a particular cluster and the stellar encounter rate, ${\displaystyle \Gamma }$.

The best fit model from the Turk & Lorimer (2013) paper suggested that the number of pulsars in a specific globular cluster, ${\displaystyle N_{\rm {psr}}}$ is

${\displaystyle \log _{e}N_{\rm {psr}}=-1.1+1.5\log _{10}\Gamma }$

The number of pulsars expected to be detectable in any given survey is then given by:

${\displaystyle N_{\rm {expected}}={\frac {N_{\rm {psr}}}{2}}{\rm {erfc}}\left({\frac {\log _{10}L_{\rm {min}}-\mu }{{\sqrt {2}}\sigma }}\right)}$

where ${\displaystyle \mu =-1.1}$ and ${\displaystyle \sigma =0.9}$ are reasonable values and ${\displaystyle L_{\rm {min}}}$ is the extrapolated luminosity sensitivity at an observing frequency of 1400 MHz (note that ${\displaystyle L_{\rm {min}}=S_{\rm {min}}D^{2}}$ where ${\displaystyle D}$ is the distance to the globular cluster).

A list of close-by globular clusters is given below:

|NGC 2808 || 09:23:03.10 || -64:51:48.6 || 9.6 || 923 ||

Cluster	Right ascension	Declination	Distance (kpc)	${\displaystyle \Gamma }$	${\displaystyle N_{\rm {known}}}$
Terzan 5	17:48:05	-24:46:48	6.9	6800	34
NGC 7078, M15	21:29:58.33	+12:10:01.2	10.4	4510	8
Terzan 6			6.8	2470
NGC 6441			11.6	2300	4
NGC 6266, M62	17:01:12.60	-30:06:44.5	6.8	1670	6
NGC 1851	05:14:06.76	-40:02:47.6	12.1	1530	1
NGC 6440			8.5	1400	6
NGC 6624	18:23:41	-30:21:39	7.9	1150	6
NGC 6681, M70	18:43:12.76	-32:17:31.6	9.0	1040
47 Tucanae, NGC 104	00:24:05.67	-72:04:52.6	4.5	1000	23
Pal 2	04:46:05.91	+31:22:53.4	27.2	929	0
NGC 6388	17:36:17.461	-44:44:08.34	9.9	899
NGC 6293	17:10:10.4	-26:34:54	9.5	847
NGC 6652			10.0	700	1
NGC 6284	17:04:28.7	-24:45:52	15.3	666
NGC 6626, M28	18:24:32.89	-24:52:11.4	5.5	648	12
M80	16:17:02.42	-22:58:33.9	10.0	532
NGC 7089, M2	21:33:27.02	-00:49:23.7	11.5	518
NGC 5286	13:46:26.81	-51:22:27.3	11.7	458
NGC 6517	18:01:50.52	-08:57:31.6	10.6		4
NGC 6539	18:04:49.68	-07:35:09.1	7.8		1
NGC 6760	19:11:12.01	+01:01:49.7	7.4		2
NGC 5904, M5	15:18:33.22	+02:04:51.7	7.5		5
NGC 5024, M53	13:12:55.25	+18:10:05.4	17.9		1
NGC 6838, M71	19:53:46.49	+18:46:45.1	4		1
NGC 5272, M3	13:42:11.62	+28:22:38.2	10.2		4
NGC 6205, M13	16:41:41.24	+36:27:35.5	7.1		5
NGC 5986	15:46:03.00	-37:47:11.1	10.4		1
M4, NGC 6121	16:23:35.22	-26:31:32.7	2.2		1
NGC 6342					1
NGC 6397	17:40:42.09	-53:40:27.6	2.2		1
NGC 6522					3
NGC 6544					2
NGC 6656, M22	18:36:23.94	-23:54:17.1	3		2
NGC 6749					1
NGC 6752	19:10:52.11	-59:59:04.4	4.0		5
NGC 7099, M30	21:40:22.12	-23:10:47.5	8.3		2
Omega Centuari, NGC 5139	13:26:47.28	-47:28:46.1	4.84

The Magellanic Clouds

The following pulsars are currently known in the small Magellanic cloud (SMC):

The following pulsars are currently known in the small Magellanic cloud (LMC):

Distant galaxies

McLaughlin et al. (2003) carried out a large-scale search for giant pulses coming from extragalactic pulsars, but did not make any convincing detections. As described below Rubio-Herrera et al. (2013) used Westerbork to search for pulsars in M31. Kondratiev et al. (2013) used the Green Bank and Arecibo telescopes to search for pulsars in nearby galaxies.