Julie Dahlstrom

STUDIES OF DIFFUSE INTERSTELLAR BANDS V. PAIRWISE CORRELATIONS OF EIGHT STRONG DIBs AND NEUTRAL HYDROGEN, MOLECULAR HYDROGEN, AND COLOR EXCESS

We establish correlations between equivalent widths of eight diffuse interstellar bands (DIBs), and examine their correlations with atomic hydrogen, molecular hydrogen, and E B?V . The DIBs are centered at ?? 5780.5, 6204.5, 6283.8, 6196.0, 6613.6, 5705.1, 5797.1, and 5487.7, in decreasing order of Pearsons correlation coefficient with N(H) (here defined as the column density of neutral hydrogen), ranging from 0.96 to 0.82. We find the equivalent width (EW) of ?5780.5 is better correlated with column densities of H than with E B?V or H2, confirming earlier results based on smaller data sets. We show that the same is true for six of the seven other DIBs presented here. Despite this similarity, the eight strong DIBs chosen are not correlated well enough with each other to suggest they come from the same carrier. We further conclude that these eight DIBs are more likely to be associated with H than with H2, and hence are not preferentially located in the densest, most UV shielded parts of interstellar clouds. We suggest that they arise from different molecules found in diffuse H regions with very little H2 (molecular fraction f < 0.01). Of the 133 stars with available data in our study, there are three with significantly weaker ?5780.5 than our mean H-?5780.5 relationship, all of which are in regions of high radiation fields, as previously noted by Herbig. The correlations will be useful in deriving interstellar parameters when direct methods are not available. For instance, with care, the value of N(H) can be derived from W ?(5780.5).

SN 2013ej - A type IIL supernova with weak signs of interaction

We present optical photometric and spectroscopic observations of supernova 2013ej. It is one of the brightest type II supernovae exploded in a nearby (

ANOMALOUS DIFFUSE INTERSTELLAR BANDS IN THE SPECTRUM OF HERSCHEL 36. I. OBSERVATIONS OF ROTATIONALLY EXCITED CH AND CH + ABSORPTION AND STRONG, EXTENDED REDWARD WINGS ON SEVERAL DIBs ∗

\sim 10

DIFFUSE ATOMIC AND MOLECULAR GAS IN THE INTERSTELLAR MEDIUM OF M82 TOWARD SN 2014J

Mpc) galaxy NGC 628. The light curve characteristics are similar to type II SNe, but with a relatively shorter (

Geometry and velocity structure of HD 44179’s bipolar jet

\sim85

SEARCHING FOR NAPHTHALENE CATION ABSORPTION IN THE INTERSTELLAR MEDIUM

day) and steeper (

ERRATUM: “ANOMALOUS DIFFUSE INTERSTELLAR BANDS IN THE SPECTRUM OF HERSCHEL 36. II. ANALYSIS OF RADIATIVELY EXCITED CH+, CH, AND DIFFUSE INTERSTELLAR BANDS” (2013, ApJ, 773, 42)

\sim1.7

Analysis of Anomalous Diffuse Interstellar Bands in the Spectrum of Herschel 36

mag (100 d)

Anomalously Broad Diffuse Interstellar Bands and Excited CH + Absorption in the Spectrum of Herschel 36

^{-1}

Behaviour of the Broadest DIBs as a Function of E(B–V)

in V) plateau phase. The SN shows a large drop of 2.4 mag in V band brightness during plateau to nebular transition. The absolute ultraviolet (UV) light curves are identical to SN 2012aw, showing a similar UV plateau trend extending up to 85 days. The radioactive