Radio Galaxy Zoo Talk

"Radio continuum detection in blue early-type weak emission line galaxies"

  • mlpeck by mlpeck

    I was going to post this one on GZ Talk as an example of independent use of GZ related publications, but I can't seem to sign in there.

    Anyway, this showed up on arxiv 15 Mar 2016: 1603.03866, A. Paswan & A. Omar, "Radio continuum detection in blue early-type weak emission line galaxies".

    From Schawinski's catalog of blue early type galaxies they examined the 76 "weak emission line" objects (that is ones that were unclassifiable in a BPT diagram) in FIRST images. Of 65 in the FIRST footprint they found 8 direct detections, and based on a stack of the remaining 57 concluded that there was significant radio continuum emission overall.

    Next, they found far IR data for 4 of their positive detections and concluded based on the ratio of far IR to RC flux that the radio emission was due to a low level of star formation rather than AGN (an entirely plausible conclusion I'm sure), and from the radio luminosities they then estimated star formation rates for their 8 detections using a formula that I'm sure is familiar to the science team, as well as upper limits to SFR for the remaining 57.

    Figures 4-6 are plots of SFR against u-r color, u-r against velocity dispersion, and SFR against velocity dispersion. Spot the junk statistics used to produce Figure 6 and the totally unwarranted conclusion they reach based on it!

    Finally they conclude that AGN feedback is responsible for suppression of star formation, which is completely conventional wisdom but seems a little odd since the sample they chose to study showed no actual evidence of ongoing AGN activity.

    I wonder if this has been accepted for publication. It's formatted for MNRAS and they thank the referee, but it's not noted as accepted on arxiv.

    Oh, and Schawinski's catalog of blue ETGs still has 215 objects both in the Vizier catalog and in the supplemental data table at MNRAS despite the original paper and just about every one that cites it (including this one) saying there are 204. Does anyone ever check things like that?

    Posted

  • zutopian by zutopian in response to mlpeck's comment.

    I wonder if this has been accepted for publication. It's formatted for MNRAS and they thank the referee, but it's not noted as accepted on arxiv.

    It was accepted and first published online March 14, 2016!
    Here is link to the paper on the webpage of MNRAS.:

    Radio continuum detection in blue early-type weak emission line galaxies
    http://mnras.oxfordjournals.org/content/early/2016/03/14/mnras.stw598.abstract?sid=507600d2-9ad9-42b1-8f8e-bafeab43a023

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  • sisifolibre by sisifolibre

    I'm not sure to understand, but if you are asking about blue ETG with possible extended radio emission, may be here are some candidates:

    http://radiotalk.galaxyzoo.org/#/subjects/ARG0001c1v

    http://radiotalk.galaxyzoo.org/#/subjects/ARG0001wqo

    http://radiotalk.galaxyzoo.org/#/boards/BRG0000002/discussions/DRG0000ev5

    May be that in this discussion there are some blue ETG candidates:
    http://radiotalk.galaxyzoo.org/#/boards/BRG0000006/discussions/DRG0000efq

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  • Dolorous_Edd by Dolorous_Edd

    Also http://radiotalk.galaxyzoo.org/#/collections/CRGS0000uo

    Posted

  • mlpeck by mlpeck in response to sisifolibre's comment.

    Is who asking about blue ETG with radio emission? It wasn't me. The OP was made here mostly because I couldn't sign in to GZ Talk, where there's a thread I think for discussion of independent uses of GZ related data/publications. Also of course the paper is somewhat relevant to this project.

    The only question I asked was more or less a rhetorical one. For some reason I find it endlessly amusing that none of the 16 co-authors of Schawinski et al. 2009 noticed that there were 215 objects in their sample of blue ETGs, not 204 as repeatedly claimed in the paper. Nor for that matter have the authors of the ∼ 3 published studies that have made direct use of that sample noted that the sample size is ≠ 204.

    This paper (the one by Paswan and Omar, not Schawinski et al.) is not very good by the way. If it was actually published in MNRAS in substantially the same form as the arxiv version I really have to wonder about the state of peer review in astronomy. They performed a laughably bad statistical "analysis" that should never have been allowed into a prestigious journal.

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  • sisifolibre by sisifolibre

    Sorry for my intrusion, my English is not very good and poorly understood.

    Posted

  • zutopian by zutopian in response to mlpeck's comment.

    Oh, and Schawinski's catalog of blue ETGs still has 215 objects both in the Vizier catalog and in the supplemental data table at MNRAS despite the original paper and just about every one that cites it (including this one) saying there are 204. Does anyone ever check things like that?

    Schawinski et al. apparently forgot to count the 11 objects, which are listed on the last page (page 5) of table 2!
    http://mnras.oxfordjournals.org/content/suppl/2013/01/19/j.1365-2966.2009.14793.x.DC1/mnras0396-0818-SD1.pdf

    588017990148816933 12:59:48.6 +08:55:57.9 0.04620 -21.28 2.177 - LINER
    588017991233110227 14:37:33.0 +08:04:43.0 0.04987 -21.62 2.353 3.6 SF
    588017991773978739 15:14:29.9 +07:35:46.8 0.04484 -20.79 2.042 - -
    588018091080351786 15:58:25.4 +32:58:07.7 0.04798 -21.87 2.295 - -
    588018254297038899 16:18:18.7 +34:06:40.1 0.04733 -21.58 2.307 2.9 SF
    588023239671087134 09:13:20.7 +17:38:27.7 0.02554 -21.33 2.238 - -
    588295840177061984 12:19:05.9 +48:49:27.7 0.04468 -20.85 2.151 - AGN+SF
    588295842320744617 11:25:07.3 +49:42:02.6 0.04997 -21.42 2.382 - -
    588297863102988421 08:43:46.7 +31:34:52.6 0.04756 -20.70 2.110 7.3 SF
    588297864718909472 09:30:31.3 +39:17:50.0 0.04605 -21.87 2.143 - -
    588848899365601360 10:26:54.6 -00:32:29.4 0.03463 -21.38 2.137 7.6 SF

    EDIT:
    I am not sure!
    In Table 1* there are given 204 blue ETGs.: 50 of those are indicated as SF!
    Table 2: On the pages 1-4 there are 51 SF and on page 5 there are 4 SF!

    '* Emission line classification results for blue early-type galaxies.

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  • ivywong by ivywong scientist, admin

    For those of you interested on the topic of blue-ETG, you might be interested in this paper too :

    https://radiotalk.galaxyzoo.org/#/boards/BRG0000009/discussions/DRG0000a41

    Happy to answer any questions on this paper which Paswan & Omar missed.
    Ivy

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