Additions, combinations, and synonyms for the Bolivian moss flora

Fifty-five mosses are newly recorded for Bolivia. Additional collection data are given for twelve mosses considered little known or rare in the country. Six new synonyms are recognized, five from Bolivia, one from Brazil: Hookeria scabripes Müll. Hal. [Callicostella scabripes (Müll. Hal.) Broth.] = Callicostella pallida (Hornsch.) Ångstr.; Leucobryum fragile Herzog = Leucobryum subobtusifolium (Broth.) B.H. Allen; Macromitrium pinnulatum Herzog = Macromitrium microstomum (Hook. & Grev.) Schwägr.; Schlotheimia vesiculata Herzog [Macromitrium vesiculatum (Herzog) Herzog] = Macromitrium stellulatum (Hornsch.) Brid.; Cyclodictyon breve Herzog = Cyclodictyon albicans (Hedw.) Kuntze; and from Brazil: Callicostella paludicola Broth. = Callicostella merkelii (Hornsch.) A. Jaeger. Three new combinations are proposed: Entosthodon subaloma (Herzog) S.P. Churchill (Goniobryum subaloma Herzog), Syntrichia xerophila (Herzog) S.P. Churchill (Tortula xerophila Herzog), Thamniopsis lepidopiloides (Herzog) S.P. Churchill (Hookeriopsis lepidopiloides Herzog)

The Kinematic Composition of MgII Absorbers

The study of galaxy evolution using quasar absorption lines requires an understanding of what components of galaxies and their surroundings are contributing to the absorption in various transitions. This paper considers the kinematic composition of the class of 0.4 < z < 1.0 MgII absorbers, particularly addressing the question of what fraction of this absorption is produced in halos and what fraction arises from galaxy disks. We design models with various fractional contributions from radial infall of halo material and from a rotating thick disk component. We generate synthetic spectra from lines of sight through model galaxies and compare the resulting ensembles of MgII profiles with the 0.4 < z < 1.0 sample observed with HIRES/Keck. We apply a battery of statistical tests and find that pure disk and pure halo models can be ruled out, but that various models with rotating disk and infall/halo contributions can produce an ensemble that is nearly consistent with the data. A discrepancy in all models that we considered requires the existence of a kinematic component intermediate between halo and thick disk. The variety of MgII profiles can be explained by the gas in disks and halos of galaxies not very much different than galaxies in the local Universe. In any one case there is considerable ambiguity in diagnosing the kinematic composition of an absorber from the low ionization high resolution spectra alone. Future data will allow galaxy morphologies, impact parameters, and orientations, FeII/MgII of clouds, and the distribution of high ionization gas to be incorporated into the kinematic analysis. Combining all these data will permit a more accurate diagnosis of the physical conditions along the line of sight through the absorbing galaxy.Comment: 34 pages including 14 postscript figures; Accepted by the Astrophysical Journal; URL http://www.astro.psu.edu/users/cwc/pubs.htm

A Bare Molecular Cloud at z~0.45

Several neutral species (MgI, SiI, CaI, FeI) have been detected in a weak MgII absorption line system (W_r(2796)~0.15 Angstroms) at z~0.45 along the sightline toward HE0001-2340. These observations require extreme physical conditions, as noted in D'Odorico (2007). We place further constraints on the properties of this system by running a wide grid of photoionization models, determining that the absorbing cloud that produces the neutral absorption is extremely dense (~100-1000/cm^3), cold (<100 K), and has significant molecular content (~72-94%). Structures of this size and temperature have been detected in Milky Way CO surveys, and have been predicted in hydrodynamic simulations of turbulent gas. In order to explain the observed line profiles in all neutral and singly ionized chemical transitions, the lines must suffer from unresolved saturation and/or the absorber must partially cover the broad emission line region of the background quasar. In addition to this highly unusual cloud, three other ordinary weak MgII clouds (within densities of ~0.005/cm^3 and temperatures of ~10000K) lie within 500 km/s along the same sightline. We suggest that the "bare molecular cloud", which appears to reside outside of a galaxy disk, may have had in situ star formation and may evolve into an ordinary weak MgII absorbing cloud.Comment: 15 pages, 4 figures, 4 tables, ApJ accepte