Abstract
Nulling pulsars are pulsars whose observed flux occasionally disappears, but the mechanism behind the cessation is not well understood. Motivated by the correlation between pulse width and nulling fraction found in Sheikh & MacDonald, we compile all 378 nulling pulsars to date with their pulse widths in a machine-readable table. We also include the observing frequency and time resolution of each pulse width measurement. Such a table will be useful for future studies of this population.
Export citation and abstract BibTeX RIS
Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
1. Introduction
Nulling pulsars are pulsars whose broadband emission occasionally ceases and then returns (e.g., Ritchings 1976). This behavior has been theorized to be due to physical changes i.e., in the pulsar's magnetosphere, rather than changes in line-of-sight (e.g., Timokhin 2010). Sheikh & MacDonald (2021) provided the most recent analysis of nulling pulsar statistics, including a search for correlations between nulling fraction (the percentage of the time that a pulsar is in a nulled state) and pulse width. The authors used the nulling pulsar data from Konar & Deka (2019) and combined it with nulling pulsar pulse widths, W10 and W50, from the ATNF pulsar catalog (Manchester et al. 2005).
Here, we present a table of nulling pulsar pulse widths with observing frequencies for use in future pulsar studies in Table 1. We include the observing frequencies because pulsar pulse width varies with frequency due to spectral distribution across the emission region (e.g., Chen & Wang 2014). In addition to the original pulsars from the 2019 list, we include all newly discovered nulling pulsars 3 through 2021 April, bringing the total number of nulling pulsars in the table to 377. We do not include intermittent pulsars (e.g., Konar & Deka 2019), rotating radio transients (e.g., McLaughlin et al. 2006), or mode-changing pulsars (Rankin 1986) although they might all be related phenomena with similar physical mechanisms in the emission region.
Table 1. The Columns of the Machine-readable Table of Nulling Pulsars Described in this Document
| Table Key | Description |
|---|---|
| index | Index |
| psr_name | The B-name of the pulsar if it has one, the J-name if it does not |
| j_name | The J-name of the pulsar |
| period_s | The pulsar's spin period, in seconds—from ATNF (Manchester et al. 2005) unless otherwise specified in the "notes" portion of the table header |
| measured_nf_flag | A binary variable flag indicating whether the pulsar has a measurement for nulling fraction |
| nulling_reference | An integer indicating the reference which described the pulsar's nulling behavior (the reference key is given below this Table) |
| W50_deg | The width of the pulse at 50% of the maximum height (e.g., full width half max) in degrees, where 360° is equivalent to one pulse period |
| W50_ms | The width of the pulse at 50% of the maximum height (e.g., full width half max) in milliseconds |
| W50_mP | The width of the pulse at 50% of the maximum height (e.g., full width half max) in milli-Periods (mP), where 1000 mP is equivalent to one pulse period |
| W50_reference | An integer indicating the reference which measured the reported W50 |
| W50_obs_freq_MHz | The observing frequency, in MHz, at which the W50 value was measured |
| W50_sampling_time_ms | The sampling time, in ms, at which the W50 data was taken |
| W10_deg | The width of the pulse at 10% of the maximum height in degrees |
| W10_ms | The width of the pulse at 10% of the maximum height in milliseconds |
| W10_mP | The width of the pulse at 10% of the maximum height in milli-Periods |
| W10_reference | an integer indicating the reference which measured the reported W10 |
| W10_obs_freq_MHz | The observing frequency, in MHz, at which the W10 value was measured |
| W10_sampling_time_ms | The sampling time, in ms, at which the W10 data was taken |
Note. Reference code keys for the nulling_reference, W50_reference, and W10_reference columns are as follows: [1) Arzoumanian et al. (1994), (2) Ashworth & Lyne (1981), (3) Bailes et al. (2020), (4) Basu et al. (2020), (5) Boyles et al. (2013), (6) Brinkman et al. (2018), (7) Burgay et al. (2006), (8) Burgay et al. (2019), (9) Burke-Spolaor et al. (2011), (10) Cameron et al. (2020a), (11) Cameron et al. (2020b), (12) Camilo & Nice (1995), (13) Champion et al. (2005), (14) Costa et al. (1991), (15) Crawford et al. (2006), (16) D'Amico et al. (1998), (17) Deneva et al. (2016), (18) Edwards et al. (2001), (19) Good et al. (2020), (20) Hobbs et al. (2004), (21) Jacoby et al. (2009), (22) Jankowski et al. (2019), (23) Johnston & Kerr (2018), (24) Johnston et al. (2020), (25) Johnston et al. (2021), (26) Joshi et al. (2009), (27) Kawash et al. (2018), (28) Kerr et al. (2014), (29) Konar & Deka (2019), (30) Kramer et al. (2003), (31) Lewandowski et al. (2004), (32) Lorimer et al. (2002), (33) Lorimer et al. (2006), (34) Lorimer et al. (1995), (35) Lynch et al. (2013), (36) Manchester et al. (2001), (37) McCulloch et al. (1978), (38) McEwen et al. (2020), (39) McLaughlin et al. (2006), (40) Morris et al. (2002), (41) Ng et al. (2015), (42) Ng et al. (2020), (43) Nice et al. (2013), (44) Guojun et al. (1995), (45) Rankin & Benson (1981), (46) Sayer et al. (1997), (47) Spiewak et al. (2020), (48) Stovall et al. (2014), (49) Tan et al. (2020), (50) Taylor et al. (1993), (51) Teplykh & Malofeev (2019), (52) Theureau et al. (2011), (53) Tiburzi et al. (2013), (54) Wang et al. (2020), (55) Young et al. (2015), (56) Zhang et al. (2019), (57) Zhao et al. (2019).
Only a portion of this table is shown here to demonstrate its form and content. A machine-readable version of the full table is available.
We envision this data set to be used in two ways. First, it provides the most current reference for all pulsars that have been observed to null. This information will be integral for use in future population studies but might also be used as a reference to radio observers, to indicate which nulling pulsars must be observed further to quantify their nulling fraction. Second, the data set provides pulse widths for nulling pulsars in the context of their observing frequency and sampling time. This context is crucial to properly normalize pulse widths using pulse width-observing frequency relationships, and, given the correlation between pulse width and nulling fraction discovered in Sheikh & MacDonald (2021), a proper normalization will likely need to be employed to fully understand nulling behavior.
2. Table Information
The table is published in machine-readable format and contains 378 entries: 340 have W50 information and 291 have W10 information.
The authors would like to acknowledge Jason Wright for providing feedback on the manuscript. This work was carried out by the Penn State branch of the Pulsar Search Collaboratory, an organization which is supported by NSF Advancing Informal STEM Learning (AISL) (awards: 1516512, 1516269). M.G.M. acknowledges that this material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under grant No. DGE1255832. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation.
Footnotes
- 3
Both newly discovered nulling pulsars and pulsars that were previously known, but had only been recently observed to null.