![[Science Operations home]](../../../generic-images/sciopshomebtn.gif){kind=small}
![[System Verification home]](../../../sys-verif/svhomebtn.gif){kind=small}
![[NIRI home]](../nirihomebtn.gif){kind=small}
| Status: some observations done Data link: not yet available Assessment: under way |
|||
| Mode: | High-background Imaging | ||
| Additional instrument verification: | tests performance of OIWFS and its interaction with the TCS using the f/14 camera; ability/usefulness of pipeline reduction of images a complex field. | ||
| Telescope verification: | Tests ability to get high Strehl ratios with tip/tilt correction, consistency and stability over the field and over time; performance at high airmass. | ||
| Proposed observing sequence: | test sequences being developed to allow for sky subtraction | ||
| OT program file: | available | ||
| Science background: | L and M Imaging of the Sgr A Complex The Galactic Center is an important laboratory for understanding the nuclear regions of moderately late-type spiral galaxies. Using NIRI, deep L' and M observations will be obtained of a 50 x 50 arcsec field centered on SgrA*, which dynamical studies suggest is associated with a super-massive compact object. These data will be used to search for emission from hot dust around SgrA*, with the goal of constraining the temperature of the accretion disk, and hence the rate of mass accretion. These data will also be used to study the spectral-energy distributions of the stars in the compact star cluster surrounding SgrA*. If the stars in the compact cluster surrounding SgrA* have `normal' photospheric properties, then they should have K-L = 2, and L = 12; however, if they are experiencing enhanced mass loss rates, as might be expected if they are subjected to an intense radiation field from the accretion disk of SgrA*, then they might show excess emission in L and M from warm circumstellar dust shells. Finally, these data will also be used to map diffuse (ie. non-stellar) emission from warm dust in the Sgr A complex. Continuum emission from hot dust could fill in the photospheric 2.3 micron CO bands, and thereby provide an explanation for the CO-weak region that has been detected near SgrA*. |
||
| Target(s): | |||
| Object | approx. RA (2000) | approx. dec (2000) | |
| Sgr A* | 17 h 42 m | -29 deg | |
| Observing condition constraints: | image quality: 20%-ile (80% achieved) sky transparency (clouds): 50%-ile (80% achieved) sky transparency (water vapour): 50%-ile sky background: 50%-ile max air mass: 2.0 |
||
| Observing time requirements: | Approx. 1 hour on-source in each filter (L' and M') | ||
| Observing time achieved: | A couple of hours in L' with 0.5 to 0.75 arcsec seeing and some cirrus | Data release date: | To be determined |
| SV team member(s) responsible for assessment: | Tim Davidge (PI), Doug Simons, Charlie Telesco | ||
Last update August 20, 2001; Joe Jensen