Performances
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
(airy radius)

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 
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~4.5x10-16 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.,  ~1.5x10-16 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)

 
#2313 - Last update : 12/04 2007

 

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