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Energies of fluorescent lines

Stefano Bianchi
 

Hi all,

how does Cloudy handle the energies of the Kalpha fluorescent lines from ionized species?
Is the neutral transition energy used for all species (apart from recombination lines from He- and H-like ions)?
For example, the fluorescent Kalpha line energy from SiII-VI is significantly different from that of SiVII, SiVIII, SiIX, etc, and this difference can be measured with current instruments (i.e. Chandra HETG). The same holds for S.
Does Chandra produce different lines from these ionized species?

Thanks,
Stefano

Guzman Fulgencio, Francisco
 

Hi Stefano,

Cloudy uses Stout database for all ions with more than 2 electrons. You can find Stout data in data/stout/ directories. You can find the energies in the .nrg files.

Cheers.

Fran




From: Main@CloudyAstrophysics.groups.io <Main@CloudyAstrophysics.groups.io> on behalf of Stefano Bianchi via groups.io <bianchi@...>
Sent: Wednesday, June 10, 2020 12:38 PM
To: Main@CloudyAstrophysics.groups.io <Main@CloudyAstrophysics.groups.io>
Subject: [Cloudy_Questions] Energies of fluorescent lines
 
CAUTION: External Sender

Hi all,

how does Cloudy handle the energies of the Kalpha fluorescent lines from ionized species?
Is the neutral transition energy used for all species (apart from recombination lines from He- and H-like ions)?
For example, the fluorescent Kalpha line energy from SiII-VI is significantly different from that of SiVII, SiVIII, SiIX, etc, and this difference can be measured with current instruments (i.e. Chandra HETG). The same holds for S.
Does Chandra produce different lines from these ionized species?

Thanks,
Stefano

Stefano Bianchi
 

Hi Fran,

thanks for your reply. I'm interested in inner-shell transitions, I'm not sure their energies can be extracted in a straightforward way from the Stout data.
However, I realized these transitions are listed in the LineLabels.txt file, and they are indeed different for each ion. Many of the energies, though, seem inaccurate (for example for mildly ionized Si). What's the reference for the inner-shell transition energies in Cloudy? Is it Kaastra & Mewe 1993?

Thanks,
Stefano

peter_van_hoof
 

Hi Stefano,

On 12/06/2020 11.45, Stefano Bianchi wrote:
Hi Fran,
thanks for your reply. I'm interested in inner-shell transitions, I'm not sure their energies can be extracted in a straightforward way from the Stout data.
However, I realized these transitions are listed in the LineLabels.txt file, and they are indeed different for each ion. Many of the energies, though, seem inaccurate (for example for mildly ionized Si). What's the reference for the inner-shell transition energies in Cloudy? Is it Kaastra & Mewe 1993?
Most of the transitions for complex ions come either from Stout or Chianti, but IIRC neither contains inner-shell transitions. There are so-called UTA transitions, which are inner-shell lines. Most of those come from open-ADAS, with some calculations by Romas Kisielius.


Cheers,

Peter.

--
Peter van Hoof
Royal Observatory of Belgium
Ringlaan 3
1180 Brussel
Belgium
http://homepage.oma.be/pvh

Stefano Bianchi
 

Hi Peter,

the energies for Si and S are very close to Kaastra & Mewe (1993), but the authors themselves warn the readers that their energies are rather inaccurate. Even the energies in the historical House (1969) are more accurate. But a recent paper gives very accurate experimental values, together with an overview of the theoretical calculations:

http://dx.doi.org/10.3847/0004-637X/830/1/26

For example, the lines in ions with >=9 electrons should only be about an eV apart between ionization stages, all blending together around 1740 eV in Si. The charge states with fewer electrons (that still leave space in the n=2
shell when excited) should be spaced about 15-20eV apart in Si. But in the list used by Cloudy (below, taken from LineLabels.txt), the low charge states are spaced by about 10eV, then suddenly Si 7-11 are all within 5eV of each other:

Si2       1.7394000
Si2       1.7398002
Si3       1.7535007
Si3       1.7539001
Si4       1.7673004
Si4       1.7681018
Si5       1.7816005
Si5       1.7819999
Si6       1.7914003
Si6       1.7923015
Si7       1.8038009
Si7       1.8038009
Si9       1.8059001
Si9       1.8059001
Si11       1.8083998
Si10       1.8088008
Si8       1.8126008
Si8       1.8126008
Si2       1.8356996
Si3       1.8557016

These differences are huge even for spectra of current missions (see e.g. the Vela X1 Chandra spectrum in the above reference) and will be crucial for the (near!) future micro-calorimeters.
How are these energies coded in Cloudy? Can they be modified easily?

Stefano