[vsnet-chat 1558] Re: (fwd) On SN host galaxy query (Gheen)

[Taichi Kato <tkato>]

Re: (fwd) On SN host galaxy query (Gheen)

> First, what is GSC magnitude?

   GSC is an abbreviation of HST Guide Star Catalog.  The catalog was
produced in order to guide the Hubble Space Telescope, and it contains
about 15 million stars.  I refer to this catalog to get "GSC magnitudes".

> What exactly is 'flux at X microns'?

   Stars and galaxies (and probably all other objects) emit infrared
light, other than the visible light.  The notation "X microns" specifies
the wavelength (color) of the infrared light.  The wavelength of the
visible light is around 0.5 micron, while infrared lights longer than
1 micron.  "Flux" means the strngth of light.

> how big of a telescope would you need to see this?

   Typical supernovae are fainter than 15-th magnitudes, but some are
brighter.  The 15-th magnitude stars can be glimpsed through a 40-cm
(typically) or a larger telescope.  Some infrequent bright supernovae
can be sometimes observed by a 10-cm telescope.  Some keen eyes can
overcome this limit, however.

Regards,
Taichi Kato

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