2005AJ....129.1968L

The Spitzer Space Telescope (formerly SIRTF) extragalactic First Look Survey covered about 5 deg² centered on (J2000.0) α=17^h18^m, δ=59°30' in order to characterize the infrared sky with high sensitivity. We used the 100 m Green Bank Telescope to image the 21 cm Galactic H I emission over a 3°x3° square, covering this position with an effective angular resolution of 9'.8 and a velocity resolution of 0.62 km/s. In the central square degree of the image the average column density is N_HI_=2.5x10²⁰/cm2 with an rms fluctuation of 0.3x10²⁰/cm2. The Galactic H I in this region has a very interesting structure. There is a high-velocity cloud, several intermediate-velocity clouds (one of which is probably part of the Draco Nebula), and narrow-line low-velocity filaments. The H I emission shows a strong and detailed correlation with dust. Except for the high-velocity cloud, all features in the N_H I_ map have counterparts in an E(B-V) map derived from infrared data. Relatively high E(B-V)/N_H I_ ratios in some directions suggest the presence of molecular gas. The best diagnostic of such regions is the peak H I line brightness temperature, not the total N_H I_: directions where T_b>12 K have E(B-V)/N_H I_ significantly above the average value. The data corrected for stray radiation have been released via the World Wide Web.