Probing the mass and star formation of high-redshift lensed galaxies with SPIFFI 3D spectroscopy

Team responsible: Marie Lemoine-Busserolle (Institute of Astronomy, Cambridge, UK)
Team members: M. Kissler-Patig (ESO, Garching), T. Contini, R. Pello, J-F Leborgne, J-P Kneib (Laboratoire D'Astrophysique, Toulouse), I. Parry (Institute of Astronomy, Cambridge)

Finding charts: A370-A5AC114-V4

We propose to use SPIFFI to make a spatially-resolved study of about 2 images of spectroscopicaly confirmed high redshift galaxies behind the cores of galaxy lensing clusters . The natural magnification due to massive galaxy clusters provides the opportunity to study young galaxies 1 to 3 magnitudes fainter than those selected in blank fields. The SPIFFI wavelength coverage (1.1 to 2.4 microns) makes it possible to detect the strong optical emission lines ([OIII] and Hα) for galaxies with 0.7< z < 3.8, allowing for the first time significant study of dynamical masses and star formation at these redshifts.

Target list
NameRA(2000)DEC(2000)Plate-Scale(s)Bands(s)Exp.time(on source)
A370-A502:39:52.86-01:35:40.32250H1.5 h
J3.5 h
AC114-V422:58:44.53-34:48:06.73250H4 h
K4 h

Additional information:
The main goal of this programme is to obtain 2D velocity maps from Hα, Hβ and [OIII] emission line for 2 star-forming lensed galaxies in the two clusters lenses AC114 (RA=22:58:47.7, DEC=-34:48:14) and A370 (RA=02:37:00, DEC=-01:48:00). For A5-370 (z = 1.341, RA=02:39:52.860, DEC=-01:35:40.320) the Hα emission falls in the SPIFFI H band and the Hβ and [OIII] emission in SPIFFI J band. In the case of AC114-V4 (z = 2.274, RA=22:58: 44.528, DEC=-34:48:06.730) the Hα emission is redshifted in SPIFFI K band and the Hβ and [OIII] emission in SPIFFI H b and. We estimate our exposure time (on source) based on our ISAAC longslit observations of the arcs. The SPIFFI sensitivity suggest that we will detect with a S/N of ~5 in a 0.25 arcsec diameter lenslet, the Hα emission in 1H30 for A370-A5 and in 4H00 for AC 114-V4. To reach the same S/N for the [OIII] emission we need 3H30 for A370-A5 and 4H00 for AC114-V4.

Observing strategy
O-S-O-O-S-O with FoV=8x8 arcsec, DIT 600s and NDIT 1s. We request a seeing < 1 arcsec. For telluric standars please select stars that are hotter than B4.