Konkoly Observatory, Budapest, Hungary
27 October 2005
The authors present a full catalogue of 269 ISOPHOT observations (291 measurements) of 181 compact objects. They were observed in staring mode with the P1 detector at 3.6 micrometer. The catalogue is split into two separated catalogues. First one contains observations with a single measurement at 3.6 um. They are 32 ISOPHOT observations of 31 compact objects. This catalogue (I) is the "default dataset" in IDA for these 32 observations.
The data set consists on:
A detailed report is available
List of caveats related to P1 staring observing mode corrected in this work:
If observations are performed in non-standard apertures, deviations from the
exact flux calibration can occur. One effect is related to the aperture
dependent responsivity calibration with the internal Fine Calibration Source
However in our data processing scheme we adopted default responsivities and the FCS calibration was not used. Therefore the photometric fluxes presented in this catalogue are not affected by this caveat. It is also known that the scaling of the signal in different apertures is non-linear with the geometric aperture size (PHT Handbook Section 10.6). Since this catalogue contains observations of compact sources located at the centre of the aperture this caveat is irrelevant in this case.
The ISOPHOT-P detectors show a non-linear response with flux.
As part of the analysis this non-linear response has been characterized and then each observation was corrected for this effect (see "empirical correction" in the data processing report).
The fluxes have been corrected for the loss of flux outside the aperture
under the assumption that the source is a point source (PHT
Handbook Section 10.12 and Table
2.3). Since the background has not been subtracted before, this correction
factor has to be applied to the background value before subtraction.
In most cases, the background is negligible, compared to source flux at 3.6um. Thus this effect has no influence on our photometric results.
The detector response, i.e. the amount of photo current per amount of
illuminated radiation, can vary, in particular due to cosmic ray hits
Handbook Section 4.2.4 and 10.8)).
This affects mainly long lasting map observations.
Since this catalogue contains typically short ON/OFF observations this caveat is irrelevant.
Staring mode observations of point sources are not background subtracted.
In the preparation of this catalogue the corresponding background measurements (if any) have been identified and subtracted from the source observation. When no dedicated background observation was available an average "empty sky" signal was subtracted (see data processing report).
The flux density values in this catalogue are not color corrected.
Gradual (transient) adjustment of the detector output signal in response
to an instantaneous flux change. Time constants can be several minutes.
Handbook Section 4.2.3 and 10.7
No transient correction algorithm is available for the P1 detector yet. In cases of unstable signals only the last part of the measurement was used (selected interactively).
The PHT OLP data product does only contain an uncertainty from the
statistical signal evaluation. It does not give any estimates of the systematic
uncertainties of all applied calibration steps. Therefore, the provided
uncertainties must be considered as minimal errors (PHT
Handbook Section 10.3).
As described in the data processing report a typical ensemble flux uncertainty was derived for a subset of the sample. This uncertainty was found to depend on the flux of the source. The formal uncertainties in the catalogue were computed as the maximum of the PIA error bars and the ensemble uncertainty.