[Lofarpwg] LOFAR LBA census draft -- ready for commenting

[Anna Bilous]

Dear all,

if you have not read the draft yet (note that the deadline is *August 30*),
here is the updated version. I have added a few sentences to the discussion
following the input from Michael. However, I really do want to draw any
physics-related conclusions (or do any theory matching) based on the sample
of spectra in this paper, since most of the spectral breaks (or potential
spectral breaks) there are subject to large, poorly known uncertainties. I
think  it would be a very useful study to do (possibly with Nenufar, but
LOFAR can be good here as well), but such things should be done carefully,
or not done at all.

Below are some replies to individual comments.

Cheers,
Anya

Joeri:
>Maybe add: "While the data used here may not use LOFAR to its full
capabilities,  and future and ongoing low-frequency observations (cf. $5.2)
may reach higher signal-to-noise, the results we present here are still the
most sensitive obtained to date."

I’m not sure about most sensitive, could be not the case for bright
classical pulsars. Changed to
“While the data used here may not use LOFAR to its full capabilities, and
future and ongoing low-frequency observations may reach higher
signal-to-noise, the results we present here still provide useful
infromation about low-frequency end of the pulsar spectra (see
Section~\ref{subsec:results}).”

> *) It's not clear to me why is $3.2 is where it is. Is that pulsar so
special? There are many other non detections. Perhaps give it some intro or
move to "results" section.

It’s one of the two closest to Earth pulsars in our sample and the one with
ATNF DMs being off by a factor of ~3 if compared to HBA census DMs. It has
been independently detected at the latter DM with FR606, so ATNF DM is most
probably wrong (or changed very rapidly in a few years), but still, it
would have been nice to have LBA detection.

> *) I think the results section could be stronger if we derive some
conclusions from the Fig. C plots. It seems to me that for all pulsars that
previously had no 100 MHz flux, this flux is
 1) below a single PL
 2) to far below that is requires a multiple PL.
I.e., evidence for a turn over around X MHz (~200?)
Perhaps you can create an "ensemble" spectrum that makes this statistically
stronger?
Because on a per pulsar basis the evidence is reasonably strong but not
solid (as you write) while as a group this is clearly the behaviour.

I think there are several pulsars with LBA fluxes extending known spectrum
while being on 1PL line, e.g. B0226+70 and others.

Patrick:

> Section 2: 2nd paragraph - Add a sentence at the end like "The
consequence is that only 88 out of the 194 pulsars which are in the HBA
census were observed and discussed here." At the moment the text doesn't
quite explicitly states if only HBA pulsars were observed, or all pulsars
HBA pointings are available for (without the pulsar necessarily being
detected).

I modified the (now) last sentence in the paragraph to clarify that: “At
present, with all HBA observations being processed and analysed (leading to
substantial changes in some of S/N estimates), we can regard the LBA census
source sample as being an arbitrary subsample of pulsars detected in HBA
census, with some preference for closer/brighter sources. “

> We adjusted pulsar period P and DM with the PSRCHIVE pro-
gram pdmp, maximizing integrated S/N of the frequency- and
time-averaged profile over the set of trial values of P and DM. REMOVE
INTEGRATED.

I’ll keep integrated (as opposed to peak) S/N.


> Section 3.2 - I agree with Joeri this should not be part of "Observations
and data reduction"

I think it does belong to Section 3.1 “Detection and ephemerides update”













On Fri, Aug 16, 2019 at 8:53 AM Anna Bilous <hanna.bilous at gmail.com> wrote:

> Dear all,
>
> please find attached the draft of LBA census. Please let us (myself,
> Louis, JM & Vlad) know if you have any comments on it. We would like
> to submit it on Aug 30 due to Louis'es graduation constraints. Sorry
> for the quite short notice, but the paper is short and very simple, so
> it should not take long to read it.
>
> Cheers,
> Anya
>
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