The second Energetic Gamma Ray Experiment Telescope (EGRET) catalog
(Thompson et al. 1995) contains 129 sources detected in time
integrated exposures at E> 100 MeV during Phases 1 and 2 of the Compton
Gamma Ray Observatory (CGRO) mission. Additional 28 sources detected in
Phase 3 of the viewing program are listed by Thompson et al.
(1996). A large percentage (60.5%) of these sources remains
unidentified till now. The main candidates for identifications are active
galactic nuclei (AGNs), isolated pulsars, supernova remnants (SNRs), and OB
star associations. Particularly, sources at low latitudes
(
) are thought to be of galactic nature (Kanbach
et al. 1996). Possible identifications of some of these sources with
SNRs (Sturner & Dermer 1995; Sturner et al.
1996; Esposito et al. 1996), pulsars (Merck et al.
1996), and star-forming regions (Kaaret & Cottam 1996)
have been recently proposed. However, most low-latitude 
-ray sources
seem to have no straightforward counterpart at other wavelengths, and it
has even been suggested that they could belong to a new type of
astrophysical objects (e.g. Merck et al. 1996).
The main problem that hinders an effective identification of the lower frequency
counterpart of low-latitude EGRET sources is the background contamination
produced by the galactic disk radiation. For radio wavelengths the fine
structure at is almost completely masked by the diffuse disk
component. If this component can be efficiently removed, new identifications
with previously unnoticed radio sources might be established.
In this paper we present a study of the radio surroundings of the -ray
source 2EG 
. This source has been rejected as a pulsar
candidate due to its spectral shape by Merck et al. (1996),
and none known SNR is close to its 95% EGRET confidence contour (see
Green 1996, for an updated list of SNRs). There are not either
nearby OB associations (Mel'nik & Efremov 1995). Recently,
Mattox et al. (1997) has found using a Bayesian analysis that
2EG can be identified with the strong flat-spectrum radio
source PKS 1830-211 with 98% confidence. This latter extragalactic
object is a well-established gravitational lens system and its
identification with 2EG , if conclusively confirmed, would
be the first of such kind. However, the centroid of the region enclosed by
the 95% confidence contour is at a galactic latitude 
,
and consequently disk contamination might be hiding other possible radio
counterparts of 2EG , like previously unnoticed SNRs in
interaction with dense molecular clouds (Aharonian & Atoyan
1996). In order to study this possibility we have made 1.42 GHz
observations of the field around 2EG 
2138 and removed the
background radiation with a filtering technique. The results support the
Mattox et al. identification of PKS 1830-211 as the first multiple image
gravitational lensed system detected by EGRET.