Talk:TXS 0506+056

not a previously-known blazar

According to the Scientific American article:

The next day, September 29, at 9:00 A.M., another optical telescope found that the Texas source was a blazar, a supermassive black hole at the center of a galaxy that sporadically flares up as matter falls into it, sending out jets aimed straight at us. Then, on October 17, the Very Large Array in New Mexico, operating at radio wavelengths, confirmed the light was coming from a blazar’s jet.

--★NealMcB★ (talk) 14:36, 16 July 2018 (UTC)

The Scientific American article is clearly incorrect. This source has been a known blazar since at least 2009 [1] [2], and a known gamma-ray blazar since 2010 [3]. Both those papers list the sub-type as BL Lac object, even more specific than just a blazar. Furthermore, the Fermi ATel from 28 September (a day before the Sci Am claim) states that the source is a blazar. Modest Genius ^talk 14:56, 16 July 2018 (UTC)

I've added a paragraph on the observational history. Modest Genius ^talk 15:08, 16 July 2018 (UTC)

Thank you - delighted to have the references and history, and contributions from an expert! Now who's going to tel Sci Am? ;) ★NealMcB★ (talk) 15:43, 16 July 2018 (UTC)

Searching Fermi data for 2014-15 flare

Re the removal of the text about an archival search of "gamma rays from the Fermi Gamma-ray Space Telescope", and the edit summary "the Nature story specifically states that Fermi did not find the earlier flare" ([4]): I think the Nature article says the Fermi team didn't find it. But the reference at [5], also cited by the Nature article, says that "a new analysis of Fermi-LAT data" was used in support of the view that "(TXS) is the only counterpart of all the neutrino emissions in the region and therefore the most plausible first non-stellar neutrino and, hence, cosmic ray source.". So it seems that some sort of reference to archival searhing of Fermi data is appropriate. But perhaps the experts here have a more nuanced view. ★NealMcB★ (talk) 16:07, 16 July 2018 (UTC)

I've now read the Padovani paper. It shows that TXS 0506+056 was emitting no more gamma rays than usual during the 2014-15 neutrino flare, though there are hints that it might have shifted to slightly higher energies (clearest in their Fig 5). Regardless, the gamma-ray emission was *far* less than the 2017 flare around the IceCube-170922A event. The paper does provide independent support for the IceCube team's association of TXS 0506+056 with the high-energy neutrino event, by disentangling gamma-ray emission from other nearby sources. I'll add some additional info to the article. Modest Genius ^talk 15:57, 21 July 2018 (UTC)

What does TXS stand for? And is it what the nickname "Texas Source" comes from?

What does TXS stand for? Is it what the nickname "Texas Source" comes from? ★NealMcB★ (talk) 17:33, 16 July 2018 (UTC)

TXS is the standard acronym for the 'Texas survey of radio sources' [6]. I've added an explanation to the article. And yes, though I've never seen the nickname used by professional astronomers. It's not a very useful nickname because there are approximately 67,000 'Texas sources'. Modest Genius ^talk 10:32, 17 July 2018 (UTC)

Is there a sky map of the extreme (TEV) gamma ray sky that shows TXS 0506+056?

Is there a sky map of the extreme (TEV) gamma ray sky that shows TXS 0506+056? ★NealMcB★ (talk) 17:35, 16 July 2018 (UTC)

E.g. getting the Fermi blazar map integrated with WikiSky would be great. Note that this blazar can be easily found in one of the unnamed circles from the Fermi blazar map by matching the constellation version of that map with the data in the article and the border info at https://upload.wikimedia.org/wikipedia/commons/f/ff/Orion_IAU.svg Alternatively if someone can combine those images and re-map them on the constellation map and point to this blazar, it would be great. ★NealMcB★ (talk) 17:54, 16 July 2018 (UTC)

Fermi only goes up to 300 GeV. Higher energies are accessible via pointed observations from the ground e.g. by MAGIC and VERITAS, which have small fields of view. As far as I am aware the only sky survey at TeV energies was by Milagro, though apparently High Altitude Water Cherenkov Experiment are working on a new one. Modest Genius ^talk 10:41, 17 July 2018 (UTC)

Great info - thanks. I'm guessing that my little labeled map should note that there is another nearby source, which may even be stronger at the Fermi energies, as previously discussed. ★NealMcB★ (talk) 18:26, 17 July 2018 (UTC)

Neutrino oscillation?

This may be a stupid question, but how do we know it originated as a ν_μ? What about neutrino oscillation? --ἀνυπόδητος (talk) 08:39, 10 August 2018 (UTC)

Good point, we don't. The cited reference carefully only refers to 'a neutrino' at the blazar and 'muon neutrino' at the IceCube detector, though doesn't explicitly discuss oscillation in between. I've rephrased that paragraph accordingly. Modest Genius ^talk 10:40, 10 August 2018 (UTC)

Cosmic ray sources?

"though no cosmic rays from TXS 0506+056 have been directly observed. " I thought that we can't directly observe cosmic ray sources since they are electricaly charged they are bent in the magnetic field of the galaxy. Is not one of the major motivations for neutrino astronomy to find the sources of cosmic rays, which they can directly observe since neutrinos are electraly neutral? Folket (talk) 12:52, 24 June 2019 (UTC)

Correct. This blazar has been inferred to produce high-energy cosmic rays, but as cosmic rays are deflected by magnetic fields there's no hope of tracing any back to that specific blazar. There may be a better way of phrasing this in the article. Modest Genius ^talk 11:07, 1 July 2019 (UTC)

misleading distance

The current text says "it is about 1.75 gigaparsecs (5.7 billion light-years) from Earth". The cited source specifically states this as a luminosity distance. I think interpreting a luminosity distance as an actual distance is unwarranted. 74.69.160.254 (talk) 08:04, 24 December 2022 (UTC)

I've edited the lead to specify that this is a luminosity distance. It's easy to calculate other distance measures from the redshift, by assuming a cosmological model. Modest Genius ^talk 12:30, 7 February 2024 (UTC)