tycohen / aoschedulingtaskforce

Noise estimates for NANOGrav 15-year pulsars with past, current, and potential instrument configurations

AO Scheduling Taskforce σTOA Estimates

Code used to aggregate pulsar parameters and estimate the TOA uncertainty referenced to the infinite frequency TOA (as described in Lam et al. 2018) for NANOGrav 15-yr pulsars with a variety of telescopes including:

• Arecibo 430 & L-band
• Arecibo L-band and S-band
• GBT 800 & L-band
• GBT L-band & VLA S-band
• CHIME & GBT L-band
• CHIME & GBT UWBR

NG15yr_totRMS.txt contains the total RMS for each pulsar at each telescope, assuming 30 min integration time per band per epoch, except at CHIME where the integration time is dec-dependent and at most 30 hours / epoch. Pulsars not visible to CHIME have their CHIME sigmas set to -2. Total noise can be scaled to different integration time using the individual noise components. See Example Usage to get individual noise components.

Summary

Best telescope (excluding Arecibo and GBT UWBR) for each pulsar based on RMS estimates taking into consideration declination-limits.

Pulsar	Best Telescope(s)	Total RMS (μs)	2nd Best Telescope(s)	Total RMS (μs)
B1855+09	CHIME-GBTL	0.4579	GBT_Rcvr_800-Rcvr_1_2	0.6280
B1937+21	GBT_Rcvr_1_2_VLAS	0.1365	GBT_Rcvr_800-Rcvr_1_2	0.3972
B1953+29	GBT_Rcvr_800-Rcvr_1_2	3.4353	GBT_Rcvr_1_2_VLAS	5.6623
J0023+0923	CHIME-GBTL	1.4126	GBT_Rcvr_800-Rcvr_1_2	2.2837
J0030+0451	CHIME-GBTL	0.8110	GBT_Rcvr_800-Rcvr_1_2	1.2065
J0125-2327	GBT_Rcvr_1_2_VLAS	0.2866	GBT_Rcvr_800-Rcvr_1_2	0.3791
J0154+1833	CHIME-GBTL	1.3340	GBT_Rcvr_800-Rcvr_1_2	2.8961
J0340+4130	GBT_Rcvr_800-Rcvr_1_2	2.0188	CHIME-GBTL	2.6424
J0406+3039	GBT_Rcvr_800-Rcvr_1_2	1.2742	CHIME-GBTL	1.4583
J0509+0856	CHIME-GBTL	1.9387	GBT_Rcvr_800-Rcvr_1_2	2.7891
J0557+1551	GBT_Rcvr_1_2_VLAS	5.3571	CHIME-GBTL	9.4253
J0605+3757	CHIME-GBTL	1.1552	GBT_Rcvr_800-Rcvr_1_2	2.0358
J0610-2100	GBT_Rcvr_800-Rcvr_1_2	1.6001	GBT_Rcvr_1_2_VLAS	2.2534
J0613-0200	GBT_Rcvr_800-Rcvr_1_2	0.3512	CHIME-GBTL	0.5378
J0614-3329	GBT_Rcvr_800-Rcvr_1_2	0.6971	GBT_Rcvr_1_2_VLAS	0.9803
J0636+5128	CHIME-GBTL	0.3880	GBT_Rcvr_800-Rcvr_1_2	0.9103
J0645+5158	CHIME-GBTL	1.4743	GBT_Rcvr_800-Rcvr_1_2	2.9557
J0709+0458	CHIME-GBTL	8.7690	GBT_Rcvr_1_2_VLAS	12.1082
J0732+2314	CHIME-GBTL	2.0457	GBT_Rcvr_800-Rcvr_1_2	2.7689
J0740+6620	CHIME-GBTL	0.5070	GBT_Rcvr_800-Rcvr_1_2	1.1347
J0751+1807	CHIME-GBTL	0.8289	GBT_Rcvr_800-Rcvr_1_2	1.1757
J0931-1902	CHIME-GBTL	1.1971	GBT_Rcvr_800-Rcvr_1_2	1.5985
J1012+5307	CHIME-GBTL	0.2555	GBT_Rcvr_800-Rcvr_1_2	0.5858
J1012-4235	GBT_Rcvr_1_2_VLAS	1.1461	GBT_Rcvr_800-Rcvr_1_2	1.6197
J1022+1001	CHIME-GBTL	0.5194	GBT_Rcvr_800-Rcvr_1_2	0.6706
J1024-0719	CHIME-GBTL	0.6790	GBT_Rcvr_800-Rcvr_1_2	0.9731
J1125+7819	CHIME-GBTL	0.3854	GBT_Rcvr_800-Rcvr_1_2	1.5188
J1312+0051	CHIME-GBTL	2.5590	GBT_Rcvr_800-Rcvr_1_2	3.7960
J1327+3423	CHIME-GBTL	7.5790	GBT_Rcvr_800-Rcvr_1_2	13.8936
J1453+1902	CHIME-GBTL	3.6239	GBT_Rcvr_800-Rcvr_1_2	5.6557
J1455-3330	GBT_Rcvr_800-Rcvr_1_2	2.4215	GBT_Rcvr_1_2_VLAS	3.8961
J1600-3053	GBT_Rcvr_1_2_VLAS	0.2576	GBT_Rcvr_800-Rcvr_1_2	0.3965
J1614-2230	GBT_Rcvr_800-Rcvr_1_2	0.9900	GBT_Rcvr_1_2_VLAS	1.4292
J1630+3550	CHIME-GBTL	3.6222	GBT_Rcvr_800-Rcvr_1_2	9.3529
J1630+3734	CHIME-GBTL	1.0158	GBT_Rcvr_800-Rcvr_1_2	1.9963
J1640+2224	CHIME-GBTL	0.7894	GBT_Rcvr_800-Rcvr_1_2	1.4290
J1643-1224	GBT_Rcvr_800-Rcvr_1_2	0.5250	GBT_Rcvr_1_2_VLAS	0.7314
J1705-1903	GBT_Rcvr_1_2_VLAS	0.5512	GBT_Rcvr_800-Rcvr_1_2	0.6364
J1713+0747	CHIME-GBTL	0.1602	GBT_Rcvr_1_2_VLAS	0.1969
J1719-1438	CHIME-GBTL	1.4084	GBT_Rcvr_800-Rcvr_1_2	1.8039
J1730-2304	GBT_Rcvr_800-Rcvr_1_2	0.8273	GBT_Rcvr_1_2_VLAS	1.1629
J1738+0333	GBT_Rcvr_1_2_VLAS	1.7060	CHIME-GBTL	1.7663
J1741+1351	CHIME-GBTL	1.6546	GBT_Rcvr_800-Rcvr_1_2	2.9330
J1744-1134	CHIME-GBTL	0.3753	GBT_Rcvr_800-Rcvr_1_2	0.5293
J1745+1017	CHIME-GBTL	0.7703	GBT_Rcvr_800-Rcvr_1_2	1.0975
J1747-4036	GBT_Rcvr_1_2_VLAS	2.7376	GBT_Rcvr_800-Rcvr_1_2	8.1213
J1751-2857	GBT_Rcvr_800-Rcvr_1_2	2.3538	GBT_Rcvr_1_2_VLAS	3.3697
J1802-2124	GBT_Rcvr_1_2_VLAS	7.9382	GBT_Rcvr_800-Rcvr_1_2	38.9509
J1803+1358	GBT_Rcvr_800-Rcvr_1_2	1.6802	CHIME-GBTL	4.0567
J1811-2405	GBT_Rcvr_800-Rcvr_1_2	1.5610	GBT_Rcvr_1_2_VLAS	1.6729
J1832-0836	CHIME-GBTL	0.7827	GBT_Rcvr_800-Rcvr_1_2	1.0559
J1843-1113	GBT_Rcvr_800-Rcvr_1_2	1.0656	GBT_Rcvr_1_2_VLAS	1.3051
J1853+1303	CHIME-GBTL	1.2095	GBT_Rcvr_800-Rcvr_1_2	1.9298
J1903+0327	GBT_Rcvr_1_2_VLAS	48.3718	CHIME-GBTL	245.6239
J1909-3744	GBT_Rcvr_800-Rcvr_1_2	0.3791	GBT_Rcvr_1_2_VLAS	0.6362
J1910+1256	CHIME-GBTL	1.5494	GBT_Rcvr_800-Rcvr_1_2	2.3068
J1911+1347	CHIME-GBTL	0.9963	GBT_Rcvr_800-Rcvr_1_2	1.4606
J1918-0642	CHIME-GBTL	0.9180	GBT_Rcvr_800-Rcvr_1_2	1.3219
J1923+2515	CHIME-GBTL	2.0951	GBT_Rcvr_800-Rcvr_1_2	3.4809
J1944+0907	CHIME-GBTL	1.6993	GBT_Rcvr_800-Rcvr_1_2	2.7582
J1946+3417	GBT_Rcvr_800-Rcvr_1_2	1.5064	GBT_Rcvr_1_2_VLAS	1.7415
J2010-1323	CHIME-GBTL	0.7913	GBT_Rcvr_800-Rcvr_1_2	1.1157
J2017+0603	GBT_Rcvr_1_2_VLAS	1.6264	CHIME-GBTL	2.0987
J2022+2534	CHIME-GBTL	1.0419	GBT_Rcvr_800-Rcvr_1_2	1.1488
J2033+1734	CHIME-GBTL	2.9154	GBT_Rcvr_800-Rcvr_1_2	5.2802
J2039-3616	GBT_Rcvr_800-Rcvr_1_2	1.4707	GBT_Rcvr_1_2_VLAS	1.7814
J2043+1711	CHIME-GBTL	1.3399	GBT_Rcvr_800-Rcvr_1_2	2.2708
J2124-3358	GBT_Rcvr_800-Rcvr_1_2	1.0778	GBT_Rcvr_1_2_VLAS	1.2549
J2145-0750	CHIME-GBTL	0.6875	GBT_Rcvr_800-Rcvr_1_2	1.0324
J2150-0326	CHIME-GBTL	1.0480	GBT_Rcvr_800-Rcvr_1_2	1.6443
J2214+3000	GBT_Rcvr_1_2_VLAS	2.0539	CHIME-GBTL	2.4623
J2229+2643	CHIME-GBTL	1.2753	GBT_Rcvr_800-Rcvr_1_2	2.6486
J2234+0611	CHIME-GBTL	1.3866	GBT_Rcvr_800-Rcvr_1_2	2.0389
J2234+0944	CHIME-GBTL	1.1274	GBT_Rcvr_1_2_VLAS	1.5500
J2302+4442	CHIME-GBTL	1.0490	GBT_Rcvr_800-Rcvr_1_2	2.1463
J2317+1439	CHIME-GBTL	0.7490	GBT_Rcvr_800-Rcvr_1_2	1.5689
J2322+2057	CHIME-GBTL	2.5864	GBT_Rcvr_800-Rcvr_1_2	4.3082

15yr_psrs.txt

Contains the parameters of each 15yr pulsar. J0437 not included b/c only visible with VLA.

Columns

• name
• period (s)
• DM (pc cm^-3)
• DEC: declination (deg)
• dtd: scintillation timescale from NE2001 (s)
• dnud: scintillation bandwidth from NE2001 (GHz)
• taud: scattering timescale from NE2001 (us)
• dist: DM distance from NE2001 (kpc)
• w50: FWHM of the L-band template (us)
• weff: effective width of the L-band template (us)
• uscale: scales intensity across pulse phase
• S_1000: flux density at 1 GHz (mJy)
• spindex: spectral index computed from log(flux ratio)/log(freq ratio) using 800/1400 for GBT pulsars, 430/1400 for AO when available, otherwise 1400/2000. Cutoff at zero
• sig_jitter: single pulse RMS jitter (us) from Lam et al. 2019 or 0.63 * W50 if not in 12.5-yr (from Fig. 7 of same paper)

The Pulsar class

Class to store an individual 15-yr pulsar

Attributes:

• name : string

pulsar name

• period : float

pulse period in seconds

• dm : float

dispersion measure in pc cm^-3

• dec : float

declination in degrees

• dtd : float

scintillation timescale in seconds

• dnud : float

scintillation bandwidth in GHz

• taud : float

scattering timescale in us

• dist : float

DM distance in kpc

• w50 : float

FWHM of L-band pulse profile in us

• weff : float

Effective width of the L-band profile in us

• uscale : float

scaling factor to distribute intensity across pulse profile

• s_1000 : float

flux density at 1 GHz in mJy

• spindex : float

spectral index

• sig_j_single : float

single-pulse RMS jitter in us

• sigmas : dict

dictionary of dictionaries of RMS components for each instrument

Methods

sigma_jitter(self, t_int)

Return intrinsic jitter noise (in us) for given integration time in seconds

add_sigmas(self, instr_name, sigma_tup)

instr_name : str

name of timing instrument

sigma_tup : tuple

tuple of RMS components

get_instr_keys(self)

returns instrument key names for sigmas dict

The PTA class

Class to store timed pulsars

Attributes:

• name : string (optional)

PTA name

• psrlist : list

list of pulsar.Pulsar objects

Methods

get_single_pulsar(self, psr_name)

return pulsar.Pulsar object whose name matches 'psr_name'

sigma_best(self, exclude=[])

Get the best instrument for each pulsar and return list of tuples of (pulsar name, instrument, sigma_tot)

Parameters

exclude : list (optional, default = [])

list of telescope name substrings to exclude when sorting RMS's

write_to_text(self, filename)

Write total RMS for each pulsar at each instrument to file

Example Usage

To get a particular pulsar's noise estimates at a particular telescope:

import cPickle
with open('NG15yr.pta', 'rb') as f:
    pta = cPickle.load(f)
j1713 = pta.get_single_pulsar("J1713+0747")
print(j1713.get_instr_keys()) # get keys for sigmas dict
print(j1713.sigmas["AO_430_Lwide_logain"])

To see which non-Arecibo telescope is best for each pulsar

import cPickle
with open('NG15yr.pta', 'rb') as f:
    pta = cPickle.load(f)
print(pta.best_sigma(exclude=["AO"]))