Atomic data from the IRON Project

Saraph, H. E.; Storey, P. J.

doi:10.1051/aas:1999437

Cited by 38 publications

(35 citation statements)

References 11 publications

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“…References for the collisional strengths (Ω): a) Blum & Pradhan (1992), b) Mendoza (1983), c) Lennon & Burke (1994), d) McLaughlin & Bell (1993, e) Zhang et al (1994), f) Saraph & Tully (1994), g) McLaughlin & Bell (2000), h) Ramsbottom et al (1998), i) Sigut & Pradhan (1995), j) Butler & Zeippen (1994), k) Keenan et al (1996), l) Galavís et al (1995), m) Saraph & Storey (1999), n) Pelan & Berrington (1995), o) Ramsbottom et al (1997), p) Saraph & Storey (1996). of the population of the level from which the line originates to the total population of the ion.…”

Section: Discussionmentioning

confidence: 99%

An ISO and IUE study of planetary nebula NGC 2440

Salas

Pottasch²,

Feibelman

et al. 2002

A&A

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Abstract. The infrared and ultraviolet spectra of planetary nebula NGC 2440 are presented. The observations were made by the Infrared Space Observatory (ISO) and the International Ultraviolet Explorer (IUE). These data, in conjunction with published optical observations have been used to derive electron temperature and density. The electron temperature increases with increasing ionization potential, from 11 000 to 18 000 K. The electron density has a constant value of 4500 cm −3 in agreement with previous determinations. The chemical abundance has been derived for the following elements; helium, carbon, nitrogen, oxygen, neon, sulfur and argon. The ionization correction factor turns out to be very small for all species except sulfur.

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Section: Discussionmentioning

confidence: 99%

An ISO and IUE study of planetary nebula NGC 2440

Salas

Pottasch²,

Feibelman

et al. 2002

A&A

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“…However, we have used the most recently determined collision strengths for both doubly and triply ionised S from Tayal & Gupta (1999) and Saraph & Storey (1999), respectively. These papers use improved and more complex methods to determine accurate collision strengths than previous, commonly used studies (e.g.…”

Section: Weak Sulphur Lines and The Origin Of Low Sulphur Abundancementioning

confidence: 99%

A mid-infrared spectroscopic survey of starburst galaxies: Excitation and abundances

Verma¹,

Lutz²,

Sturm³

et al. 2003

A&A

133

236

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Abstract. We present spectroscopy of mid-infrared emission lines in twelve starburst regions, located in eleven starburst galaxies, for which a significant number of lines between 2.38 and 45 µm were observed with the ISO Short Wavelength Spectrometer, with the intention of providing a reference resource for mid-infrared spectra of starburst galaxies. The observation apertures were centred on actively star forming regions, including those which are inaccessible at optical wavelengths due to high levels of obscuration. We use this data set, which includes fine structure and hydrogen recombination lines, to investigate excitation and to derive gas phase abundances of neon, argon, and sulphur of the starburst galaxies. The derived Ne abundances span approximately an order of magnitude, up to values of ∼3 times solar. The excitation ratios measured from the Ne and Ar lines correlate well with each other (positively) and with abundances (negatively). Both in excitation and abundance, a separation of objects with visible Wolf-Rayet features (high excitation, low abundance) is noted from those without (low excitation, high abundance). For a given abundance, the starbursts are of relatively lower excitation than a comparative sample of H II regions, possibly due to ageing stellar populations. By considering the abundance ratios of S with Ne and Ar we find that, in our higher metallicity systems, S is relatively underabundant by a factor of ∼3. We discuss the origin of this deficit and favour depletion of S onto dust grains as a likely explanation. This weakness of the mid-infrared fine structure lines of sulphur has ramifications for future infrared missions such as SIRTF and Herschel since it indicates that the S lines are less favourable tracers of star formation than is suggested by nebular models which do not consider this effect. In a related paper (Sturm et al. 2002), we combine our results with spectra of Seyfert galaxies in order to derive diagnostic diagrams which can effectively discriminate between the two types of activity in obscured regions on the basis of excitation derived from detected mid-infrared lines.

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“…Incorporating these shifts leads to better agreement between the calculated and experimental energies, without the greatly increased computational cost of carrying out the scattering calculation including fine-structure interactions. This procedure was discussed and the effects illustrated for scattering from Ca 7+ by Saraph & Storey (1996). The theoretical energies quoted in Table 2 were calculated in this way except for those in italics, which have been empirically corrected as described in B98a, using the experimental data available for the higher terms of the 3s 2 3p 2 3d configuration.…”

Section: The Scattering Targetmentioning

confidence: 99%