stormnick
commented
3 years ago Part 2: trying to get data for the star "Gaia DR2 5453496726522668160". Here is VizieR photometry viewer, with the picture for convenience. Notice specifically the point from WISE W4 band (22.1 micro meters). It has the flux density of "1.90 10^-3 Jy" (Jy = 10^-26 W/m^2/Hz). W4 band is 22.1 micro meters or about 1.36 10^13 Hz. Converting flux density to vF(v) gives about 2.58 10^-16 W/m^2. On the other hand, SEDBYS gives the following information for the same star. Around the same wavelength, the point has value of 1 10^-17 W/m^2 (almost 1 order of magnitude off). To double check that the data point is taken from the same place, here is the latex table of the values. The last entry with the same band (22.1 micro meters) has the value of 0.00011 10^-13 W/m^2 = 1.1 10^-17 W/m^2, just like it has been seen in the graph. The source is "Cutri2012vd", which leads to the WISE publication indeed. Just for triple check, I have found the entry of that point using VizieR: W4 gives magnitude of 9.103. And using either this or this converter, that gives back the original flux density of approximately 1.90 * 10^-3 Jy (or at least within the same magnitude range, given that I am not using the exactly same filter converter). So I am not sure why, but it seems to not be the same? Did SEDBYS somehow find a different W4 point? Because other values (e.g. W2/W3 filters) seem to be correct? Or is the problem lies with the VizieR somehow?
Hello,
Thank you a lot for the software. I have been trying to test it out and I am not sure whether I am doing something wrong, but I seem to be getting way less data points than by just using VizieR Photometry normally? 2 examples I have tested:
1) Gaia DR2 6808630685903354752. It has only been classified as LPV candidate by Gaia (btw: it might be misclassification). As an example, here is the result from VizieR at 1 arcsec. And here is the result from SEDBYS at 1 arcsec. OK, I thought that maybe VizieR is pulling from some catalogues that SEDBYS is not (although from your paper I got the impression that it should get at least the same results as VizieR). BTW: I have tried both 1 and 10 arcsec searches, but it does not change anything for SEDBYS.
2) V* VV Car. Orion-type star (if we trust SIMBAD classification). Here is 1 arcsec search from VizieR. Here is 1 arcsec search from SEDBYS and 2 arcsec search from SEDBYS. So 1 arcsec search seems to not find IRAS points at 100 μm (according to VizieR that data point is 0.74 arcsec away from center). 2 arcsec search seems to be better, but again, I am not sure I found all of the same points as VizieR.
Am I missing something here? Am I supposed to manually add all of the catalogues as VizieR to get at least the same result as it? Then what about VV Car star? Why does it only find the same IRAS data point only at 2 arcsec search radius (unlike VizieR at 1 arcsec radius)? Or should I be using some extra parameters during query?
Any answers or help will be appreciated.