User talk:SkyFlubbler/Archives/2023/June

HyperLeda diameters
I have been surveying HyperLeda recently, due to my steadfastness in the belief that there must be angular diameters out there other than NED's. I found 2 diameter estimates; one (https://leda.univ-lyon1.fr/fG.cgi?n=a106&o=PGC037477) is the usual measurement of D25 (In the case of the extremely large Abell 1413 BCG, an angular diameter of 1.176 arcminutes.) The other (https://leda.univ-lyon1.fr/ledacat.cgi?PGC+139724++++++++++++++++++++) is 1.07+/- 0.05 arcminutes, but it is stated that this is log D25. When I accessed the meaning of log D25, It said that log D25 is the value of the D25 diameter in arcminutes into (Meaning multiplied with?) 0.1 arcminutes. An example of such a case is given. If the angular diameter of an object is 10 arcminutes, then the log D25 value will be 0.2 arcminutes. This made me confused, because 10×0.1 is 1. I am sorry If I am wrong with the calculations, I just want to know if these diameters can be applied or not. I am also sorry if I appear to be grasping at straws just for a small passage saying that Abell 1413-BCG is among the largest galaxies known, because I have a feeling that galaxy size is not talked about much anymore. Lastly, I apologize if I appear to be bad at Math, because I want to become an astronomer too.The Space Enthusiast (talk) 05:40, 6 June 2023 (UTC)


 * I am actually planning to also include the HyperLEDA database in the list for a few months now, as it can also be assessed to give a value of the physical diameters, so that we have another list of sources besides just using the NASA/IPAC Database. The only problem that I have is how to reconcile it with the current list.
 * Regarding log D25, the value listed there is the exponent. So you have to raise 10 by that amount. So 10^1.07 = 11.7489. Since that is 0.1 arcmin, that means this is 1.17489 or 1.175 arcmin. SkyFlubbler (talk) 05:48, 6 June 2023 (UTC)
 * Thank you so much! The reconciliation will be difficult, however. The Space Enthusiast (talk) 15:26, 6 June 2023 (UTC)
 * Thanks. I am sorry if I disturbed you, but when measuring the R90 diameters of galaxies such as ESO 383-76, are we including stars within the intracluster light, which is not part of the galaxy? The Space Enthusiast (talk) 01:30, 22 June 2023 (UTC)

Sersic/De Vaucouleurs profiles
While reading Kluge et al's paper on the structure of brightest cluster galaxies and the intracluster light, I had an idea that galaxy sizes could be calculated via the Sersic/De Vaucouleurs/R^1/4 profiles. Is this possible? Do note that this is for Original Research purposes. I also read that the ratio of the size of the BCG and the size of the ICL is on average between 0.1-0.4. Of course, the issue of the ICL continues to make me restless and empty, which is why I am asking you. The Space Enthusiast (talk) 02:26, 26 June 2023 (UTC)