A B S T R A C TWe present deep, high-resolution optical spectra of two Galactic bulge planetary nebulae (PN), M 1-42 and M 2-36. The spectra show very prominent and rich optical recombination lines (ORLs) from C, N, O and Ne ions. Infrared spectra from 2:4-197 mm were also obtained using the Short and Long Wavelength Spectrometer (SWS and LWS) on board ISO. The optical and infrared spectra, together with archival IUE spectra, are used to study their density and thermal characteristics and to determine elemental abundances.We determine the optical and UV extinction curve towards these two bulge PN using observed H I and He II recombination line fluxes and the radio free -free continuum flux density. In the optical, the reddening curve is found to be consistent with the standard Galactic extinction law, with a total to selective extinction ratio R ; AðVÞ/ EðB 2 VÞ ¼ 3:1. However, the extinction in the UV is found to be much steeper, consistent with the earlier finding of Walton, Barlow & Clegg.The rich ORL spectra from C, N, O and Ne ions detected from the two nebulae have been used to determine the abundances of these elements relative to hydrogen. In all cases, the resultant ORL abundances are found to be significantly higher than the corresponding values deduced from collisionally excited lines (CELs). In M 2-36, the discrepancies are about a factor of 5 for all four elements studied. In M 1-42, the discrepancies reach a factor of about 20, the largest ever observed in a PN. M 1-42 also has the lowest Balmer jump temperature ever determined for a PN, T e ðBJÞ ¼ 3560 K, 5660 K lower than its [O III] forbidden line temperature.We compare the observed intensities of the strongest O II ORLs from different electronic configurations, including l4649 from 3s-3p, l4072 from 3p-3d, l4089 from 3d-4f, and l4590 and l4190 from the doubly excited 3s 0 -3p 0 and 3p 0 -3d 0 configurations, respectively. In all cases, in spite of the fact that the ratios of the ORL to CEL ionic abundances span a wide range from ,5-20, the intensity ratios of l4649, l4072, l4590 and l4190 relative to l4089 are found to be nearly constant, apart from some small monotonic increase of these ratios as a function of electron temperature. Over a range of Balmer jump temperature from 3500-8100 K, the variations amount to about 20 per cent for the 3s-3p and 3p-3d transitions and a factor of 2 for the primed transitions, and are consistent with the predictions of the current recombination theory. Our results do not support the claim by Dinerstein, Lafon & Garnett that the relative intensities of O II ORLs vary from nebula to nebula and that the scatter is largest in objects where the discrepancies between ORL and CEL abundances are also the largest.We find that the ORL to CEL abundance ratio is highly correlated with the difference between the temperatures yielded by the [O III] forbidden line ratio and by the H I Balmer jump, providing the strongest evidence so far that the two phenomena, i.e. the disparity between ORL and CEL temperature and abundance ...

The rotation curve (RC) of the Milky Way out to ∼ 100 kpc has been constructed using ∼ 16, 000 primary red clump giants (PRCGs) in the outer disk selected from the LSS-GAC and the SDSS-III/APOGEE survey, combined with ∼ 5700 halo K giants (HKGs) selected from the SDSS/SEGUE survey. To derive the RC, the PRCG sample of the warm disc population and the HKG sample of halo stellar population are respectively analyzed using a kinematical model allowing for the asymmetric drift corrections and re-analyzed using the spherical Jeans equation along with measurements of the anisotropic parameter β currently available. The typical uncertainties of RC derived from the PRCG and HKG samples are respectively 5-7 km s −1 and several tens km s −1 . We determine a circular velocity at the solar position, V c (R 0 ) = 240 ± 6 km s −1 and an azimuthal peculiar speed of the Sun, V ⊙ = 12.1 ± 7.6 km s −1 , both in good agreement with the previous determinations. The newly constructed RC has a generally flat value of 240 km s −1 within a Galactocentric distance r of 25 kpc and then decreases steadily to 150 km s −1 at r ∼ 100 kpc. On top of this overall trend, the RC exhibits two prominent localized dips, one at r ∼ 11 kpc and another at r ∼ 19 kpc. From the newly constructed RC, combined with other constraints, we have built a parametrized mass model for the Galaxy, yielding a virial mass of the Milky Way's dark matter halo of 0.90 +0.07 −0.08 × 10 12 M ⊙ and a local dark matter density, ρ ⊙,dm = 0.32 +0.02 −0.02 GeV cm −3 .

We present empirical metallicity-dependent calibrations of effective temperature against colours for dwarfs of luminosity classes IV and V and for giants of luminosity classes II and III, based on a collection from the literature of about two hundred nearby stars with direct effective temperature measurements of better than 2.5 per cent. The calibrations are valid for an effective temperature range 3,100 -10,000 K for dwarfs of spectral types M5 to A0 and 3,100 -5,700 K for giants of spectral types K5 to G5. A total of twenty-one colours for dwarfs and eighteen colours for giants of bands of four photometric systems, i.e. the Johnson (U BV R J I J JHK), the Cousins (R C I C ), the Sloan Digital Sky Survey (SDSS, gr) and the Two Micron All Sky Survey (2MASS, JHK s ), have been calibrated. Restricted by the metallicity range of the current sample, the calibrations are mainly applicable for disk stars ([Fe/H] −1.0). The normalized percentage residuals of the calibrations are typically 2.0 and 1.5 per cent for dwarfs and giants, respectively. Some systematic discrepancies at various levels are found between the current scales and those available in the literature (e.g. those based on the infrared flux method IRFM or spectroscopy). Based on the current calibrations, we have re-determined the colours of the Sun. We have also investigated the systematic errors in effective temperatures yielded by the current on-going large scale low-to intermediateresolution stellar spectroscopic surveys. We show that the calibration of colour (g − K s ) presented in the current work provides an invaluable tool for the estimation of stellar effective temperature for those on-going or upcoming surveys.