254 citations · 3.7k across the 112 of their papers we have counts for
9 papers · 1 filter
On the Use of Field RR Lyrae as Galactic Probes. II. A new S calibration to estimate their metallicity
J. Crestani, M. Fabrizio, V. F. Braga +33
We performed the largest and most homogeneous spectroscopic survey of field RR Lyraes (RRLs). We secured 6,300 high resolution (HR, R35,000) spectra for 143 RRLs (11…
Effective temperatures of red supergiants estimated from line-depth ratios of iron lines in the YJ bands, 0.97--1.32 micron
Daisuke Taniguchi, Noriyuki Matsunaga, Mingjie Jian +10
Determining the effective temperatures (Teff) of red supergiants (RSGs) observationally is important in many fields of stellar physics and galactic astronomy, yet some significant…
Mg II and Fe II fluxes of luminous quasars at z ~ 2.7 and evaluation of the Baldwin effect in the flux-to-abundance conversion method for quasars
Hiroaki Sameshima, Yuzuru Yoshii, Noriyuki Matsunaga +12
To investigate the chemical abundance of broad-line region clouds in quasars at high redshifts, we performed near-infrared spectroscopy of six luminous quasars at z ~ 2.7 with the…
Light and colour variations of Mira variables in the Small Magellanic Cloud
Yoshifusa Ita, John W. Menzies, Patricia A. Whitelock +6
The goal of this paper is to characterise the light variation properties of Mira variables in the Small Magellanic Cloud. We have investigated a combined optical and near infrared…
On the separation between RR Lyrae and Type II Cepheids and their importance for distance determination: the case of Cen
V. F. Braga, G. Bono, G. Fiorentino +11
The separation between RR Lyrae (RRLs) and Type II Cepheid (T2Cs) variables based on their period is debated. Both types of variable stars are distance indicators and we aim to pro…
On the Metamorphosis of the Bailey diagram for RR Lyrae stars
G. Bono, V. F. Braga, J. Crestani +37
We collected over 6000 high-resolution spectra of four dozen field RR Lyrae (RRL) variables pulsating either in the fundamental (39 RRab) or in the first overtone (9 RRc) mode. We…
The effect of surface gravity on line-depth ratios in the wavelength range 0.97-1.32 μm
Mingjie Jian, Daisuke Taniguchi, Noriyuki Matsunaga +10
A line-depth ratio (LDR) of two spectral lines with different excitation potentials is expected to be correlated with the effective temperature (). It is possible t…
Magnetic field structure of the Galactic plane from differential analysis of interstellar polarization
Tetsuya Zenko, Tetsuya Nagata, Mikio Kurita +4
A new method for measuring the global magnetic field structure of the Galactic plane is presented. We have determined the near-infrared polarization of field stars around 52 Cephei…
Variable stars in the Sh 2-170 HII region
Tirthendu Sinha, Saurabh Sharma, A. K. Pandey +7
We present multi-epoch deep (20 mag) ~band photometric monitoring of the Sh 2-170 star-forming region to understand the variability properties of pre-main-sequence (PM…