Wide-field submm imager for next generation telescopes
This table sums up the expected (Artemis – 5760 bolometer pixels) and measured (P-Artemis – 256 bolometer pixels) performances of the instrument.
| Instrument |
Wavelength (µm) |
FOV |
Beam |
Pixel size |
NEFDa (mJy/beam) |
Relative imaging speedb |
| ArTéMiS/APEX |
200 350 450 350+450d |
0.9’x1.0′ 4.1’x2.3′ 4.1’x2.3′ 4.1’x2.3′ |
4.2” 7.3” 9.4” 9.4” |
1.7” 3.9” 3.9” 3.9” |
(3000)c 1000 (700) 800 (400) 800 (400) |
(0.3) 6 (12) 6 (15) 12 (27)d |
| P-ArTéMiS/APEX |
200 450 |
0.5’x0.5′ 1.0’x1.0′ |
4.2” 9.4” |
1.7” 3.9” |
(7500) 2000c |
(0.01) 0.3 |
| SABOCA | 350 | 1.2′f | 7.3” | 12” | (350)g | (1)g |
| SHARC-2 | 350 | 2.6’x1.0′ | 8.5” | 4.8” | 1000 | 1 |
| SCUBA-2 | 450 | 7.4’x7.4′ | 7.5” | 6.2” | (500)h |
(20)h |
| LABOCA-1 | 870 | 11.4′f | 18.2” | 30” | 120 | 50 |
(a) Expected NEFD performance per detector assuming an elevation of 50° and PWV = 0.6 mm for 450 µm and 350 µm observations, which occurs 25% of the winter time at APEX; the quoted NEFD values at 200 µm assume PWV = 0.2 mm (i.e., best 10% winter conditions at the APEX site). The numbers given in parentheses represent goals that should be achieved after a full understanding of the instruments, while the other values represent sensitivities which either have already been achieved or can be achieved after commissioning, scaling from the successful results of P-ArTéMiS in November 2007.
(b) Imaging speed relative to SHARC-2 on the CSO at 350 µm for mapping cold dust emission. This is defined as the speed at which areas of the sky can be imaged (at full resolution) to a given equivalent surface brightness sensitivity. The wavelength normalization assumes a dust temperature Td= 15 K and a dust emissivity index ß=1.5 (local Universe), equivalent to Td=48 K, ß= 1.5 at a redshift z~2.2 typical of submillimeter galaxies (high-z Universe).
(c) Under the best 10% winter conditions at the APEX site (PWV = 0.2 mm).
(d) The 350+450 µm row gives the estimated performance of ArTéMiS after co-adding the data taken with the 350 µm and 450 µm arrays.
(e) P-ArTéMiS has a typical detector NEP~4.5×10-16 W/Hz0.5, i.e., a factor of ~3 worse than the PACS arrays, as this prototype uses ”free” arrays not selected for Herschel. ArTéMiS will use optimized arrays with detector NEPs comparable to PACS, i.e., ~1.5×10-16 W/Hz0.5 (Billot et al. 2006).
(f) The field of views of SABOCA and LABOCA-1 are not instantaneously sampled: observing a minimum of 16 positions is required to obtain a fully-sampled image.
(g) Under the same conditions assumed for ArTéMiS at 350 µm, i.e., PWV = 0.6 mm, which occurs ~25% of the winter time at APEX.
(h) Under PWV<=0.9 mm which occurs ~25% of the winter time at Mauna Kea.
Last update: 02/04/2008 (V. Minier)