arfgen (arfgen-1.70.4) [xmmsas_20060628_1801-7.0.0]

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Description

Generates an OGIP-compliant ([4]) ancillary response file (ARF).
The ARF contains a table listing area values
(the column `SPECRESP`)
for a number of different energy ranges
(the columns `ENERG_LO` and `ENERG_HI`).
The ARF can be used in conjunction
with the response matrix file (RMF, generated by **rmfgen**)
to allow fitting
of particular spectral models against the observed spectral data.
The actual choice of fitting package is entirely up to the user,
the only prerequisite is that it is OGIP-compliant.
The most widely used package is expected to be Xspec.

Specifically, **arfgen**
takes calibration information provided by the CAL,
performs the necessary corrections for instrumental factors
depending on the user's requirements,
and the state of spectral data,
and formats the output such that it is
compliant with [4].
It is this operation that is described here;
details of individual CCF constituents and how the CAL processes
such data are beyond the scope of this document,
and the reader should refer to the
Calibration Access and Data Handbook for such information
([1]).

The following table summarises the factors used to generate the ARF, and
the status of the corresponding code needed to model that factor
in **arfgen**:

Item |
Description | Status |

1 | Telescope Effective Area | Implemented |

2 | Filter Transmission | Implemented |

3 | Quantum Efficiency | Implemented |

4 | Complex region selection | Implemented |

5 | Spatial variation of source | Implemented |

6 | Source position specification | Implemented |

7 | Encircled energy correction (point source) | Implemented |

8 | RMF dataset i/p optional | Implemented |

9 | Pattern support | Implemented |

10 | Flux loss due to pile-up | Not implemented |

11 | Bad pixel correction | Implemented |

12 | Bad column correction | Implemented |

13 | CCD gaps | Implemented |

14 | Out of FOV/observing window | Implemented |

15 | Out-of-time event smearing (PN) | Implemented |

Item 10 will be considered in future versions and is discussed in section .

Whether a factor is taken into account by **arfgen**
in the generation of the ARF
can be controlled by individual parameters with the prefix `model`. For example,
to correct for filter transmission, the parameter `modelfiltertrans` should be
set to `true`.

- Effective Area, Filter Transmission, Quantum Efficiency and Grating attenuation
- Spatial region settings

- Spatial variation of source

- Source Position

- Encircled energy correction
- Optional RMF dataset as input
- Pattern support
- Timing and Burst modes
- Flux loss due to pile-up
- CCD gap and bad pixel corrections
- Out of time event correction

XMM-Newton SOC/SSC -- 2006-06-28