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Results and Code for "A broad survey of spectro-temporal properties from FRB20121102A"

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A broad survey of spectro-temporal properties from FRB20121102A

Reference: "A broad survey of spectro-temporal properties from FRB20121102A", Chamma, Mohammed A. ; Rajabi, Fereshteh ; Kumar, Aishwarya ; Houde, Martin. Oct. 4 2022. Submitted to MNRAS. arxiv:2210.00106, ADS:2022arXiv221000106C

Measurements and Figures

All measurements and plots of the bursts are available in the results/ folder. Each row lists the burst name and DM the measurements were performed at. Each burst is measured over a range of DMs between 555 to 575 pc/cm^3.

Measurements are available as csv spreadsheets. Spreadsheets are broken down by their respective publication. For a spreadsheet with all bursts combined see 'AllMeasurements_10003rows_Aug27.csv'. These spreadsheets can be loaded in any spreadsheet program or with pandas. For example:

df = pd.read_csv('AllMeasurements_10003rows_Aug27.csv').set_index('name')

Below is figure showing an example measurement. Figures analogous to the one shown below for all bursts and at each DM are available as large PDF files provided via request.

Measurement Example

Documentation

The spreadsheets included in this repo are arranged by one measurement per row under the following columns:

Note:

  • Plaintext columns like "slope (mhz/ms)" indicate a measurement.
  • Italicized columns indicate information about how the measurement was taken, such as "time_res (s)".
  • Stricken column names indicate a deprecated column and normally should not be used.
Column Name Description
name The name of the burst file measured, potentially suffixed with a letter (e.g., “a”, “b”, “c”) denoting the sub-pulse
DM The particular trial DM used to perform measurements
center_f The center frequency of the burst as measured by frbgui
center_f_err The propagated uncertainty on center_f
slope (mhz/ms) The sub-burst slope, obtained from the cotangent of the fit angle
slope error (mhz/ms) The propagated uncertainty on the slope
theta The angle of the semi major axis of the fit ellipse measured counter-clockwise from the positive y-axis
red_chisq Reduced chi-squared indicating the goodness-of-fit of the 2D Gaussian to the 2D ACF
amplitude Amplitude of the 2D Gaussian fit. Not normalized.
xo Central x-position (time) of the 2D gaussian fit to the 2D-ACF
yo Central y-position (frequency) of the 2D gaussian fit to the 2D-ACF
sigmax Standard deviation in x (time if vertical) of the 2D gaussian fit to the 2D-ACF
sigmay Standard deviation in y (frequency if vertical) of the 2D gaussian fit to the 2D-ACF
angle The fit angle. Equivalent to theta up to a difference of pi/2 due to the ambiguity between axes when fitting
amp_error The fit uncertainty on the amplitude
xo_error The fit uncertainty on xo
yo_error The fit uncertainty on yo
sigmax_error The fit uncertainty on sigmax
sigmay_error The fit uncertainty on sigmay
angle_error The fit uncertainty on angle
slope_abs The absolute value of slope (mhz/ms). If negative, this indicates a potential measurement issue
slope_over_nuobs 'slope_abs’ / ‘center_f’. In the TRDM, this is proportional to 1/’tau_w_ms’
slope_over_nuobs_err The propagated 2D gaussian fit uncertainty for ‘slope_over_nuobs’.
recip_slope_over_nuobs The reciprocal of slope_over_nuobs
slope_abs_nuobssq 'slope_abs’ / ‘center_f**2’. In the TRDM, this is proportional to a constant.
min_sigma Same as either sigmax or sigmay, whichever is smaller
max_sigma Same as either sigmax or sigmay, whichever is larger
min_sigma_error Same as either sigmax_error or sigmay_error, associated with whichever sigma is smaller
max_sigma_error Same as either sigmax_error or sigmay_error, associated with whichever sigma is larger
tau_w The sub-burst duration in milliseconds as defined in Chamma et al. (2022).
tau_w_error The propagated uncertainty on tau_w (ms)
tau_w_ms The sub-burst duration in milliseconds as defined in Chamma et al. (2022). An alias of tau_w. Units are implied by the choice of coordinates when fitting
bandwidth (mhz) Best-fit bandwidth for the sub-pulse in MHz
bandwidth error (mhz) Propagated uncertainty for the bandwidth in MHz
f_res (mhz) The frequency resolution (MHz) of the final waterfall used for the FRBGUI measurements
time_res (s) The time resolution (seconds) of the final data array used for the FRBGUI measurements
downf The factor by which the file was downsampled in frequency from FRBGUI from the original waterfall
downt The factor by which the file was downsampled in time from FRBGUI from the original waterfall
fchans The number of frequency channels remaining after the downsample in FRBGUI
tchans The number of time channels remaining after the downsample in FRBGUI
tsamp_width The number of time channels set by the user in FRBGUI used for measurement (i.e., the width of the waterfall)
subbg_start (ms) The time, in ms, from the start of the file that the user-defined background sample begins
subbg_end (ms) The time, in ms, from the start of the file that the user-defined background sample ends
sksigma The sigma chosen for the SK-SG filter, which performs RFI removal
skwindow The window chosen for the SK-SG filter, which performs RFI removal
regstart_a When using regions, the start of the “a” subpulse region in ms
regend_a When using regions, the end of the “a” subpulse region in ms
regstart_b When using regions, the start of the “b” subpulse region in ms
regend_b When using regions, the end of the “b” subpulse region in ms
background The size of the background subpulse region in ms. Used to pad sub-pulses with zeroes, which improves measurement stability. Background region is assumed to start from 0 ms
sigma_t The product of min_sigma and time_res (s). This is a (poor) measure of burst duration. Use tau_w or tau_w_ms for duration instead
tau_w_old The sub-burst duration as defined and used in Chamma et al. (2021). Due to the choice of coordinates when performing fits, this form can be subject to larger uncertainties when the burst is near vertical
t_from_sigma The product of min_sigma and sin(theta). This is a (poor) measure of burst duration when finding fits with physical coordinates
sigma_t_ms 'sigma_t’ in ms. See sigma_t
tau_w_ms_old tau_w_old in milliseconds

Special thanks to Dr. Sofia Sheikh for contributions to this table.

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