Sharpless notes that Sh 2-53 consists of "About six detached portions". The area is prominent at both radio and infrared frequencies.
Avedisova places the nebula in the complex star formation region
SFR 18.18-0.30, which includes 4 molecular clouds, a methanol maser and at least 4 additional HII regions visible at radio and infrared frequencies.
You can view a good black and white hydrogen-alpha image
here.
This radio study finds 6 radio sources in the region of Sh 2-53 and gives a distance estimate of 4500 pc.[
1]
The region is prominent in infrared as can be seen in this
Spitzer image.
This nebula is mentioned in connection to gamma ray source
2EG J1825-1307, which is assigned a distance estimate of 4300 parsecs. SIMBAD identifies this gamma ray source with the pulsar PWN G18.0-0.7 and the supernova remnant SNR 018.0-00.7.[
2]
This is in the same area of sky as the Scutum supershell.[
3]
Notes
1. ^ Kassim, Namir E., Weiler, Kurt W., Erickson, William C., et al. (1989).
"Improved estimates of galactic H II region emission measures and filling
factors - Low-frequency VLA observations near Sharpless 53", The
Astrophysical Journal, Vol. 338, 152-161. [1989ApJ...338..152K]
2. ^ Yadigaroglu, I.-A. & Romani, Roger W. (1997). "Gamma-Ray Pulsars and
Massive Stars in the Solar Neighborhood", The Astrophysical Journal, Vol.
476, 347. [1997ApJ...476..347Y]
3. ^ Callaway, Matthew B., Savage, Blair D., Benjamin, Robert A., et al.
(2000). "Observational Evidence of Supershell Blowout in GS 018-04+44: The
Scutum Supershell", The Astrophysical Journal, Vol. 532, 943-969.
[2000ApJ...532..943C]