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OEJV# Publication's title Author   Date
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0033Confirmation of 177 objects in the NSV Catalogue as red long period variables
635 kB
John Greaves2006-05-31
 Colours are derived from online surveys for suspected variables in the NSV having good positions and a red subset of the resultant data is assessed against the ASAS3 online time series database

Simbad object(s): NSV 166, NSV 244, NSV 326, NSV 329, NSV 350, NSV 443, NSV 502, NSV 605, NSV 620, NSV 1043, NSV 1071, NSV 1120, NSV 1171, NSV 1196, NSV 1214, NSV 1237, NSV 1564, NSV 1660, NSV 1675, NSV 1698, ...

comments8

Peter James Firth wrote 2006-06-01:
I would question the data analysis for NSV 2904 and 3391 on the basis of too few points.

The authors email address appears not to be working at present.

John Greaves wrote 2006-06-01:
The author's email address does appear to be working at present, hence why I am aware of this comment. Though I must confess it seems to be very lagged for some reason, emails are taking several hours to get to me, as far as I can, including emailing to self as test.

RESPONSE

NSV 2904 is safe enough even in ASAS3 data, due to a distinct arcuate feature of the ilk not randomly created by ASAS3 data, a pattern only generated by true form, and NSVS confirms this
http://skydot.lanl.gov/nsvs/star.php?num=12474997&mask=15636

NSV 3391 is quite safe indeed, as can be seen here

http://www.astrouw.edu.pl/cgi-asas/asas_variable/070617-2437.0,asas3,0,0,500,0

however, that is not the same plot as in the paper, that being the plot for an object roughly 0.6 arcminutes distant, as can be seen now I check the ASAS3 generated coords against the title coords which were the input. Something went awry during data plotting via the cgi generator, and it looks like I missed the fact on proof reading. I've noticed a couple of typos in the paper too, despite haven't checked all several times before submission.

Both stars are safe. An error in data presentiation for one has been made.

John Greaves wrote 2006-06-01:
I wrote

"despite haven't checked all several times before submission."

I meant

"despite having checked all several times before submission."

The typos are creeping into the typo notes!

Peter James Firth wrote 2006-06-02:
I would have liked to know what percentage of the NSV stars did not have a 2MASS star within 2 arc sec? This is a key parameter since if this was a large percentage it would perhaps suggest that the positional data available for some NSV stars is unreliable?

What is the explanation for the outliers on the graph presented?

Some charts, such as that for NSV 350 are based on ASAS stars that have quoted positions some way apart (–7941.8 to –7941.3). Are some of the “messy” graphs contaminated with readings from other stars?

What email address do readers use to contact you?
variabilitiness-at-yahoo.com
john__g-at-fsmail.net?

John Greaves wrote 2006-06-02:
"I would have liked to know what percentage of the NSV stars did not have a 2MASS star within 2 arc sec? This is a key parameter since if this was a large percentage it would perhaps suggest that the positional data available for some NSV stars is unreliable?"

The proximity, to within two arcsecs, of a 2MASS star is inherent within the fact that 2MASS photometry was available and quoted, this is a strange question.

The position of many NSV catalogue stars is unreliable. As the paper states, the coincidence of colour, position and variability for all these objects, each of the entirety of which had it's field double checked for meaningful contamination, weighs goodly evidence towards the conclusion.

"Some charts, such as that for NSV 350 are based on ASAS stars that have quoted positions some way apart (–7941.8 to –7941.3). Are some of the “messy” graphs contaminated with readings from other stars?"

It is fundamental to both ASAS3 and NSVS data that they consist of photometric entities, not stars. These entities may tally to stars on a one to one basis, or they may not. The lightcurves presented were those with inherent structure whether contaminated by internal and/or external scatter. The datasets downloaded by people and placed into graphs rarely reveal this, use of the online cgi generator makes the reality clear and enables people to assess the ASAS3 region of space being given photometry for, as opposed to some idealized "star".

It is in the nature of ASAS3 and NSVS data that there is insufficient information with which to define which photon came from where. The papers quoted for these surveys explain the resolution matter, copies of said papers can be found in arxiv.org via author search. This sort of thing is unavoidable in wide field surveys.

The email address is the one on the paper. It is the one by which I received notification of this comment via the OEJV robot. I have received no direct emails from you.

It is unavoidable, from your questioning both in terms of pedantry and in especially in terms of trying to score points relative to email address, not to ask if you are a member of the Remote Astronomy Society (the email address attack being a common practice of that group), as I have undergone several attacks by said members in the past for having dared to make clear chronic shortcomings in the astronomy therefrom.

If you are not so connected, I apologize. And if not, please read up on ASAS3 and NSVS data, the points you make will be clarified by such information, thus why these papers are referenced in OEJV 33. The 2MASS point has no meaning within the context of the use of the UCAC2 dataset to anchor these positions, former being inherent in latter. The scatter does not detract from the pattern.

You are evidently going over this paper with a fine tooth come, I'm sure more points of apparently significant but truly minor context will arise upon further examination of both this and future papers.

Such is publishing, such is progress.

James Bedient wrote 2006-06-22:
The risk of studies like this, relying on extracting large numbers of stars from catalogues based on color data, then eyeballing ASAS light curves to make a determination as to type, is that errors that could easily be detected by researching previously published data will creep through.

NSV 4727 is not only not a "red variable", it is about as far from that category as can be - in fact, it was identified by Mr. Greaves himself in a prior publication (IBVS 5699, #80) as an SDOR. There are also many earlier publications (dating back to 1933's ApJ 78, 87) readily available on ADS and identifying this star as a Be type.

With the software tools available today, such as SIMBAD, VizieR and ADS, there's really no excuse for not crosschecking each and every star in a list like this against existing data and publications.

John Greaves wrote 2006-06-22:
Damn, I missed that one.

Well spotted Jim.

Indeed, that shouldn't have gotten past the selection criteria I used, I notice it just sneaks in at red-J 3.1.

At the time of writing it wasn't in SIMBAD nor ADS so the cross checking didn't work because it couldn't, I did lots of cross checking, but that's no excuse, I missed one that I should've been aware of because I posted it to IBVS. Incidentally, it wouldn't be in VSX yet either.

No, I do not keep a record of my own publications, whether that's right or wrong.

Cheers

John

James Bedient wrote 2006-07-26:
I would point out that NSV 2904 mentioned in the first comment was named as a Mira variable in "On five Mira variables in Orion and Canis Major", Kazarovets et al., IBVS #5435. I stumbled over this as I was cross-referencing Ross variables, this one being number 156 on Ross' lists.


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