Universiẗat, Diss., 2000--Kiel.

The Virginia Tech Spectral-Line Survey (VTSS) is a series of 10-degree wide, arcminute-resolution images of the warm ionized interstellar medium (WIM) within the Milky Way for declinations greater than -15 degrees. The Wisconsin Hydrogen-Alpha Mapper (WHAM) studies the kinematics and distribution of this same material on an angular scale of one degree. Comparing the spatially-resolved images of the VTSS with WHAM's high spectral resolution images shows that the ISM's characteristics appear to be very similar at both degree and arcminute scales --- we see similar structures, and notice the same [S II]/H-alpha trend between those structures at both degree and arcminute scales. VTSS fields show three basic types of structures --- compact clouds with diameters greater than several degrees, those that are 1-degree or less in diameter, and extended filaments that differ from the clouds by spanning several degrees in length but having thicknesses of only a few tens of arcminutes. The latter two morphological types cannot be observed by WHAM. Additionally, VTSS data confirms that the [S II] intensity values are directly proportional to H-alpha intensities, a result that is also observed at degree resolutions. Finally, VTSS data show that [S II]/H-alpha ratios are, on average, nearly six times higher in the filaments. This would indicate that collisional excitation of singly-ionized sulfur ions is the dominant emission source within filaments. In clouds, the lower [S II]/H-alpha values observed are evidence that the H-alpha recombination line of photo-excited neutral hydrogen dominates. Because automating the VTSS was a key part of obtaining many of the images used in this project, I begin with a discussion of general observatory automation. I then address the specific processes and techniques used in automating the VTSS before discussing data collection and reduction techniques. / Ph. D.

We report on high dispersion spectroscopy of the Ha absorption line of the cool DA white dwarf G 29 -38. This is the star for which a recently detected infrared excess has been suggested to be due to a possible brown dwarf companion by Zuckerman and Becklin (1986, 1987). Three echelle spectra obtained at the Multiple Mirror Telescope and at the Kitt Peak Mayall 4m telescope in 1987 December show no evidence for radial velocity variations larger than -'1.1 ± 8.7 km s -1 and are used to derive a weighted heliocentric radial velocity Vr = 33.7 ± 4.3 km s -1 for the white dwarf. No emission component from the hypothesized secondary star is detected. These negative results do not constitute strong evidence against the companion hypothesis, since the expected orbital velocity of the white dwarf component could be quite small, and the companion's line emission could be too faint to be detected. However, the observation of a sharp absorption line core restricts the possible rotation of the white dwarf to < 40 km s -1 and ensures that any surface magnetic field has a strength < 105 gauss. These results make it unlikely that the DA white dwarf has previously been in a cataclysmic variable accretion phase.

In this paper we analyze the small C1.5 class solar flare observed on June 30th 2013 by the Swedish Solar Telescope. The evolution of asym- metries in the H-alpha line profile of the solar flare was studied where it could be seen how the number of red asymmetric regions had a maximum value near the beginning of the flare and then decreases rapidly in the first 4 minutes of the observations. This could be interpreted as a correlation with the HXR and microwave emissions of the impulsive phase of the flare as these emissions also typically have a similar rapid increase and decrease of emission intensity.

Beta Lyrae is a complex binary star system with a 13-day orbital period containing two massive stars that are in the process of mass reversal accretion. The primary star is the higher mass star which is gaining mass from the secondary star. This reversal mass accretion causes gas to build and form a disk around the primary star. The disk is geometrically and optically thick. Previous interferometric studies in Optical and Infrared wavelengths have shown that a bipolar jet exists in the system and suggest that the jet contributes to the H-alpha emission. Meanwhile, other studies have suggested that the disk contributes to the H-alpha emission. We have taken into account various factors to model the emission of H-alpha from Beta Lyrae. The observed profile is double-peaked and varies with orbital phase. We found that the jet produces a single-peak for H-alpha emission. Meanwhile, the disk produces a double-peak for H-alpha emission if it is based on Keplerian motion. We use our model to interpret the observed H-alpha emission variations in the line shape with orbital phase.

One phase of formation of medium- and low-mass stars is the optically visible phase known as the pre-main-sequence or PMS phase. In order to further the understanding of this phase, more of these PMS objects need to be identified and classified. Previous techniques have used photometry to identify possible PMS objects by their characteristic Hα emission. Once identified these objects can be studied spectroscopically yielding complete PMS classification. This study develops a method to locate these emission objects that overcomes two limitations of previous techniques. The first limitation is the need for the creation of reddening maps. It is eliminated by the creation of a reddening free Hα wide/narrow index for the selection of emission objects. The second limitation is the requirement of the creation of mosaics to study the entire region of interest. This limitation is overcome by the construction of a wide-angle observation facility. This makes it possible to obtain the entire region of interest in a single frame. Once tested to ensure the validity of the method, the wide-angle Hα wide/narrow procedure is applied to several young open clusters. The development of the index and the results of its application to the clusters are presented. Also, an examination into how the results can be used to address some of the questions currently surrounding the PMS is included. Finally, a guideline for the implementation of the method into future studies is discussed.

Using the Dominion Astrophysical Observatory's 1.2-m McKellar Telescope, we have obtained spectra on 81 stars from the Hyades Cluster, the Coma Cluster, and selected H-beta standard stars. These spectra cover from 4500 Å to 6900 Å which includes both the H-β and H-α absorption lines. The H-β absorption line has a long history of being used as a temperature index and more recently, calibration of an H-α index has been established for photometric observations. Through spectrophotometric comparison of temperature indices from the H-α and H-β absorption lines we find the expected strong correlation between photometric indices based on the strength of these two lines. This result confirms that the H-α index is a strong indicator of temperature.

学位プログラム名: 京都大学大学院思修館 / 京都大学 / 新制・課程博士 / 博士(総合学術) / 甲第23343号 / 総総博第16号 / 新制||総総||3(附属図書館) / 京都大学大学院総合生存学館総合生存学専攻 / (主査)教授 山敷 庸亮, 教授 寶 馨, 准教授 浅井 歩 / 学位規則第4条第1項該当 / Doctor of Philosophy / Kyoto University / DFAM

We use Integral Field Unit (IFU) data for a subset of galaxies in the MaNGA (Mapping Nearby Galaxies at Apache Point Observatory) sample to investigate the environmental dependence of H-alpha properties for nearby star-forming galaxies. We characterize the non-AGN H-alpha emission for galaxies living in different host environments with radial gradient measurements, half-light radii, as well as measures of concentration and asymmetry. We find that global specific star formation rates (sSFR) are lower in nearby star-forming galaxies in groups and clusters compared to those in the field, and the lowest in high density environments such as group or cluster centres. From the resolved data we find that the overall reduction in H-alpha emission in star-forming galaxies in denser environments occurs across the face of these galaxies, suggesting starvation as a primary quenching mechanism. We further find that H-alpha disks are truncated in group galaxies that live nearer the center of the halo compared to those in the outer halo or field, which may be due to ram pressure stripping in these dense environments. / Thesis / Master of Science (MSc) / In order to understand the evolution of galaxies over time, it is necessary to determine the relative importance of external and internal factors that affect galaxy star formation. We know that galaxies in dense environments have less star formation (are quenched) compared to galaxies in the field. However, the mechanisms that dominate this quenching are less well constrained. We use a sample of galaxies in the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey to investigate the dependence of star formation on other galaxy properties as well as properties of the host environment. We find that galaxies have reduced H-alpha emission, a signature of star formation, across the entire face of the galaxy in groups and clusters compared to galaxies in the field. We further find that galaxies nearer the centre of the group or cluster halo have truncated H-alpha disks compared to galaxies in the outer part of the halo or in the field.

The spectroscopic and photometric observations of the optical counterparts to the Be/X-ray binary systems GRO J2058+42 and V0332+53 (BQ Cam), taken with RTT150 (Russian-Turkish 1.5 meter Telescope), are presented in this study. The distance, color and the reddening estimates for both sources, obtained via photometric observations, are consistent with the previous results. The results of our spectroscopic observations performed between May 2006 and June 2008 for optical counterpart to GRO J2058+42 indicate that the double-peaked emission line profile turns into a single-peaked emission after the last outburst of the system. Furthermore, the spectra of the source show clear evidence for the changes in the ratio of the double peaks of H alpha emission line indicative of the precession of the high-density regions confined in the disk. Unlike the spectra of counterpart to GRO J2058+42, the spectra of BQ Cam, taken between September 2006 and December 2007, exhibit single-peaked H alpha and HeI (Lambda 7065 Angstrom) emission lines. In addition, the equivalent width values of H alpha emission lines, shifts from the the laboratory wavelengths for H alpha and HeI emission lines and the variation in optical brightness of BQ Cam show a close correlation.