erosita-forum

Hi Matteo

If you're making merged exposure maps, the exposure time is the equivalent exposure for the *on-axis* combined eROSITA effective area.

You can take the effective area at a particular energy from the ARF file here: https://erosita.mpe.mpg.de/dr1/eSASS4DR ... R1_arfrmf/

Cheers

Jeremy

Dear Joe I would need to see a more complete description of how you are using srctool to understand the problem better. However, I can give some comments: The exposure time given by srctool isn't the same as in exposure maps - it is more of an on-time. See the docs. I would not use the rates from sp...

Hi Erwin

I'm glad you've managed. However, remember that there's light leak in the soft band that's present in the pipeline-produced maps. There's also some (relatively mild) flaring in the harder band (see Merloni et al. 2.3-5.0 keV map).

Jeremy

We've put some half sky maps here from Zheng et al.: https://erosita.mpe.mpg.de/dr1/AllSkySu ... yMaps_dr1/

However, they are projected maps and are not in Healpix format.

Hi - expmap can be slow for large maps or polar regions. If it's still printing messages, it's likely working. Probably the easiest way to speed it up is by enabling OpenMP parallelisation. You can try setting the OMP_NUM_THREADS environment variable to a value >1 to run on more than one core. Jeremy

There is still one question. When I extract the spectra from a large area, the photon counts given by *srctool* do not match the value I directly count from the event file. The total number of photon counts in the spectrum file is about 6,000 and when I consider the same region, I count to ~38,000 ...

Hi Ziqian Hua 1)I find that the photon counts given by the *srctool* are less than the value which I directly count. The question is how *srctool* calculate the GTI and where to find the GTI information? B.T.W. It seems that *srctool* cannot correctly calculate the exposure? For my region, the EXPOS...

Hi I would like to plot a PSF radial profile in the 0.2--2.3 keV range and compare it with the profile of a real source. However, I have some questions: Firstly, there are many different types of PSF files in the caldb, and I am not sure which one to choose. For a source in the survey, tm1_2dpsf_190...

Hi Joseph * Are these 2D images appropriate to be used as image convolution kernels? Yes, that is how srctool does its PSF correction, and what ermldet uses in image mode source detection. They are derived from PANTER ground-based measurements. Each HDU is a different energy. You may want to make th...

Dear Hui We plan to publish these in the standard way so they are listed in Aladin, etc. Hopefully we will do this in the next few weeks. Until then, they can be loaded into the desktop Aladin tool by the URLs on https://erosita.mpe.mpg.de/dr1/AllSkySurveyData_dr1/HalfSkyMaps_dr1/ Best wishes Jeremy