  The soft X-ray instrument eROSITA on board the Spectrum-Roentgen-Gamma (SRG)
observatory has successfully completed four of the eight planned all-sky
surveys, detecting almost one million X-ray sources during the first survey
(eRASS1). The catalog of this survey will be released as part of the first
eROSITA data release (DR1). Based on X-ray aperture photometry, we provide flux
upper limits for eRASS1 in several energy bands. We cover galactic longitudes
between $180^{\circ}\lesssim l \lesssim 360^{\circ}$ (eROSITA-DE). These data
are crucial for studying the X-ray properties of variable and transient
objects, as well as non-detected sources in the eROSITA all-sky survey data. We
performed aperture photometry on every pixel of the SRG/eROSITA standard
pipeline data products for all available sky tiles in the single detection band
($0.2 - 2.3$ keV). Simultaneously, we performed the same analysis in the
three-band detection at soft ($0.2-0.6$ keV), medium ($0.6-2.3$ keV), and hard
($2.3-5.0$ keV) energy bands. Based on the combination of products for the
individual bands, we are also able to provide aperture photometry products and
flux upper limits for the $0.2 - 5.0$ keV energy band. The upper limits were
calculated based on a Bayesian approach that utilizes detected counts and
background within the circular aperture. The final data products consist of
tables with the aperture photometry products (detected counts, background
counts, and exposure time), a close-neighbor flag, and the upper flux limit
based on an absorbed power-law spectral model ($\Gamma=2.0, \; N_{\rm
H}=3\times10^{20}$ cm$^{-2}$). The upper limits are calculated using the
one-sided $3\sigma$ confidence interval (CL) of a normal distribution,
representing CL = 99.87\%. The aperture photometry products allow for an easy
computation of upper limits at any other confidence interval and spectral
model. ...
