Abstract
Doublet line emission and absorption are common in astronomical sources (e.g. [OIII], [O II], NaD, MgII). In many cases, complex kinematics in the emitting source can cause the doublet lines to merge, making characterization of the source kinematics challenging. Here, we present a non-parametricmethod for resolving merged doublet lines when the line ratio andwavelength difference are known. The method takes as input only the line ratio and wavelength difference, using these quantities to resolve the components of the doublet without resorting to fitting (e.g. using multiple Gaussians) ormaking any assumptions about the components' line profiles (save that they are the same for both components). The method is simple, fast, and robust. It is also ideal for visualization.We show that the method recovers line profiles of merged emission lines in simulated data. We also show, using simulated data and mathematical analysis, that the method does not significantly increase noise levels in the extracted lines, and is robust to background contamination. We demonstrate the strength of the method by applying it to strongly merged [OIII] 5007/4959 Å in Active Galactic Nuclei. A PYTHON implementation of the method is provided in the appendix.
| Original language | English |
|---|---|
| Pages (from-to) | 3782-3793 |
| Number of pages | 12 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 481 |
| Issue number | 3 |
| Early online date | 14 Sep 2018 |
| DOIs | |
| Publication status | Published - 1 Dec 2018 |
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Keywords
- ISM: jets and outflows
- ISM: kinematics and dynamics
- Line: profiles
- Methods: analytical
- Stars: kinematics and dynamics
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science
Cite this
A simple non-parametric method for resolving merged doublet lines : Insights into complex kinematics and outflows. / Villforth, Carolin; Underwood, Tom L.; Tolson, Mark; Modha, Nikhil.
In: Monthly Notices of the Royal Astronomical Society, Vol. 481, No. 3, 01.12.2018, p. 3782-3793.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - A simple non-parametric method for resolving merged doublet lines
T2 - Insights into complex kinematics and outflows
AU - Villforth, Carolin
AU - Underwood, Tom L.
AU - Tolson, Mark
AU - Modha, Nikhil
N1 - Accepted for publication in MNRAS (changes from v1: comparison of method to fitting procedures and additional tests of method added)
PY - 2018/12/1
Y1 - 2018/12/1
N2 - Doublet line emission and absorption are common in astronomical sources (e.g. [OIII], [O II], NaD, MgII). In many cases, complex kinematics in the emitting source can cause the doublet lines to merge, making characterization of the source kinematics challenging. Here, we present a non-parametricmethod for resolving merged doublet lines when the line ratio andwavelength difference are known. The method takes as input only the line ratio and wavelength difference, using these quantities to resolve the components of the doublet without resorting to fitting (e.g. using multiple Gaussians) ormaking any assumptions about the components' line profiles (save that they are the same for both components). The method is simple, fast, and robust. It is also ideal for visualization.We show that the method recovers line profiles of merged emission lines in simulated data. We also show, using simulated data and mathematical analysis, that the method does not significantly increase noise levels in the extracted lines, and is robust to background contamination. We demonstrate the strength of the method by applying it to strongly merged [OIII] 5007/4959 Å in Active Galactic Nuclei. A PYTHON implementation of the method is provided in the appendix.
AB - Doublet line emission and absorption are common in astronomical sources (e.g. [OIII], [O II], NaD, MgII). In many cases, complex kinematics in the emitting source can cause the doublet lines to merge, making characterization of the source kinematics challenging. Here, we present a non-parametricmethod for resolving merged doublet lines when the line ratio andwavelength difference are known. The method takes as input only the line ratio and wavelength difference, using these quantities to resolve the components of the doublet without resorting to fitting (e.g. using multiple Gaussians) ormaking any assumptions about the components' line profiles (save that they are the same for both components). The method is simple, fast, and robust. It is also ideal for visualization.We show that the method recovers line profiles of merged emission lines in simulated data. We also show, using simulated data and mathematical analysis, that the method does not significantly increase noise levels in the extracted lines, and is robust to background contamination. We demonstrate the strength of the method by applying it to strongly merged [OIII] 5007/4959 Å in Active Galactic Nuclei. A PYTHON implementation of the method is provided in the appendix.
KW - ISM: jets and outflows
KW - ISM: kinematics and dynamics
KW - Line: profiles
KW - Methods: analytical
KW - Stars: kinematics and dynamics
UR - http://www.scopus.com/inward/record.url?scp=85054252609&partnerID=8YFLogxK
U2 - 10.1093/mnras/sty2528
DO - 10.1093/mnras/sty2528
M3 - Article
VL - 481
SP - 3782
EP - 3793
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 3
ER -