L. M. Haffner
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View article: The Hα sky in three dimensions
The Hα sky in three dimensions Open
We combine parallax distances to nearby O stars with parsec-scale resolution three-dimensional dust maps of the local region of the Milky Way (within 1.25 kpc of the Sun) to simulate the transfer of Lyman continuum photons through the inte…
View article: The GBT Diffuse Ionized Gas Survey (GDIGS): Discrete Sources
The GBT Diffuse Ionized Gas Survey (GDIGS): Discrete Sources Open
The Green Bank Telescope Diffuse Ionized Gas Survey (GDIGS) traces ionized gas in the Galactic midplane by observing radio recombination line (RRL) emission from 4 to 8 GHz. The nominal survey zone is 32.°3 > ℓ > −5°, ∣ b ∣ < 0.°5. Here, w…
View article: Methods for Averaging Spectral Line Data
Methods for Averaging Spectral Line Data Open
The ideal spectral averaging method depends on one’s science goals and the available information about one’s data. Including low-quality data in the average can decrease the signal-to-noise ratio (S/N), which may necessitate an optimizatio…
View article: Methods for Averaging Spectral Line Data
Methods for Averaging Spectral Line Data Open
The ideal spectral averaging method depends on one's science goals and the available information about one's data. Including low-quality data in the average can decrease the signal-to-noise ratio (SNR), which may necessitate an optimizatio…
View article: The GBT Diffuse Ionized Gas Survey (GDIGS): Discrete Sources
The GBT Diffuse Ionized Gas Survey (GDIGS): Discrete Sources Open
The Green Bank Telescope (GBT) Diffuse Ionized Gas Survey (GDIGS) traces ionized gas in the Galactic midplane by observing radio recombination line (RRL) emission from 4-8 GHz. The nominal survey zone is $32.3^{\circ}> {\ell} > -5^{\circ}$…
View article: Heliophysics Science Community Contributions to Addressing Climate Change
Heliophysics Science Community Contributions to Addressing Climate Change Open
Whitepaper #296 in the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033. Main topics: basic research; infrastructure/workforce/other programmatic. Additional topics: ground-based missions/projects; other programmatic; st…
View article: The Diffuse Ionized Gas Halo of the Large Magellanic Cloud
The Diffuse Ionized Gas Halo of the Large Magellanic Cloud Open
The Large Magellanic Cloud (LMC) has an extensive H α emission halo that traces an extended, warm ionized component of its interstellar medium. Using the Wisconsin H α Mapper telescope, we present the first kinematic H α survey of an exten…
View article: Discovery of High-velocity Hα Emission in the Direction of the Fermi Bubble
Discovery of High-velocity Hα Emission in the Direction of the Fermi Bubble Open
Wisconsin H-Alpha Mapper observations reveal high-velocity H α and [N ii ] λ 6584 emission lines in the same direction and velocity as ultraviolet absorption-line features that have been previously associated with the biconical gamma-ray l…
View article: The Effect of Bars on the Ionized ISM: Optical Emission Lines from Milky Way Analogs
The Effect of Bars on the Ionized ISM: Optical Emission Lines from Milky Way Analogs Open
Gas interior to the bar of the Milky Way has recently been shown to be the closest example of a low-ionization (nuclear) emission region (LI(N)ER) in the universe. To better understand the nature of this gas, a sample of face-on galaxies w…
View article: Discovery of diffuse optical emission lines from the inner Galaxy: Evidence for LI(N)ER-like gas
Discovery of diffuse optical emission lines from the inner Galaxy: Evidence for LI(N)ER-like gas Open
Optical emission line observations from the inner Galaxy show that the Milky Way hosts the closest known example of a LI(N)ER.
View article: Discovery of High-Velocity H-Alpha Above Galactic Center: Testing Models of the Fermi Bubble
Discovery of High-Velocity H-Alpha Above Galactic Center: Testing Models of the Fermi Bubble Open
Wisconsin H-Alpha Mapper (WHAM) observations reveal high-velocity and [NII]$\lambda6584$ emission lines in the same direction and velocity as ultraviolet absorption-line features that have been previously associated with the biconical gamm…
View article: The GBT Diffuse Ionized Gas Survey: Tracing the Diffuse Ionized Gas around the Giant Hii Region W43
The GBT Diffuse Ionized Gas Survey: Tracing the Diffuse Ionized Gas around the Giant Hii Region W43 Open
The Green Bank Telescope Diffuse Ionized Gas Survey (GDIGS) is a fully sampled radio recombination line (RRL) survey of the inner Galaxy at C -band (4–8 GHz). We average together ∼15 Hn α RRLs within the receiver bandpass to improve the sp…
View article: Geocoronal Hydrogen Emission Variation Over Two Solar Cycles
Geocoronal Hydrogen Emission Variation Over Two Solar Cycles Open
Ground‐based hydrogen Balmer‐α observations from Northern midlatitudes span multiple solar cycles, facilitating investigation of decadal scale variations, including natural variability in the hydrogen response to solar geophysical changes.…
View article: Constraining Balmer Alpha Fine Structure Excitation Measured in Geocoronal Hydrogen Observations
Constraining Balmer Alpha Fine Structure Excitation Measured in Geocoronal Hydrogen Observations Open
Cascade contributions to geocoronal Balmer α airglow line profiles are directly proportional to the Balmer β / α line ratio and can therefore be determined with near simultaneous Balmer β observations. Due to scattering differences for sol…
View article: Warm Ionized Medium throughout the Sagittarius–Carina Arm
Warm Ionized Medium throughout the Sagittarius–Carina Arm Open
Wisconsin H-Alpha Mapper observations of H α and [S ii ] λ 6716 emission are used to trace the vertical distribution and physical conditions of the warm ionized medium along the Sagittarius–Carina arm. CO emission, tracing cold molecular g…
View article: SDSS IV MaNGA: Deep observations of extra-planar, diffuse ionized gas around late-type galaxies from stacked IFU spectra
SDSS IV MaNGA: Deep observations of extra-planar, diffuse ionized gas around late-type galaxies from stacked IFU spectra Open
We have conducted a study of extra-planar diffuse ionized gas using the first\nyear data from the MaNGA IFU survey. We have stacked spectra from 49 edge-on,\nlate-type galaxies as a function of distance from the midplane of the galaxy.\nWi…
View article: SDSS-IV MaNGA: the impact of diffuse ionized gas on emission-line ratios, interpretation of diagnostic diagrams and gas metallicity measurements
SDSS-IV MaNGA: the impact of diffuse ionized gas on emission-line ratios, interpretation of diagnostic diagrams and gas metallicity measurements Open
Diffuse ionized gas (DIG) is prevalent in star-forming galaxies. Using a sample of 365 nearly face-on star-forming galaxies observed by Mapping Nearby Galaxies at APO, we demonstrate how DIG in star-forming galaxies impacts the measurement…
View article: First performance results of a new field‐widened spatial heterodyne spectrometer for geocoronal H<sub>α</sub> research
First performance results of a new field‐widened spatial heterodyne spectrometer for geocoronal H<sub>α</sub> research Open
A new, high‐resolution field‐widened spatial heterodyne spectrometer (FW‐SHS) designed to observe geocoronal Balmer α (H α , 6563 Å) emission was installed at Pine Bluff Observatory (PBO) near Madison, Wisconsin. FW‐SHS observations were c…
View article: A Study of the Warm Ionized Medium Throughout the Sagittarius-Carina Arm
A Study of the Warm Ionized Medium Throughout the Sagittarius-Carina Arm Open
We present velocity-channel maps and analysis of the warm ionized medium (WIM) throughout the Sagittarius- Carina arm at Galactic longitudes 20 1000 pc along the far Carina arm. Physical conditions of the ionized gas are analyzed using t…