ner_tags: O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Wavelength I-Wavelength O O B-Formula I-Formula I-Formula I-Formula O O O O O O B-CelestialObject I-CelestialObject O B-Telescope O O O O O O O B-CelestialObject I-CelestialObject O O O O O B-Wavelength I-Wavelength O B-Formula I-Formula I-Formula I-Formula O O O O O O O O O B-Wavelength I-Wavelength O O O O O O O O O O B-Wavelength I-Wavelength O O O O O O O B-Wavelength B-Wavelength O O B-Wavelength I-Wavelength O B-CelestialObject O B-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O B-Wavelength I-Wavelength O O O O O B-Wavelength O O O O O O O O O O O B-Wavelength I-Wavelength O O O O O O B-Formula I-Formula I-Formula I-Formula I-Formula I-Formula O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Wavelength I-Wavelength O O O O O O B-CelestialObject I-CelestialObject O O O O O O O B-Wavelength O O O O O O O O O O O O O O B-CelestialObject O O O O B-CelestialObject I-CelestialObject B-Citation I-Citation I-Citation I-Citation O B-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O B-Wavelength I-Wavelength O O O O O O O O O O O O O B-Wavelength I-Wavelength O O O O O O O O O O O B-Wavelength O B-Wavelength I-Wavelength O O O O O O O O O O O O O O O O B-Wavelength I-Wavelength O B-Wavelength O O O O O O O O O B-Wavelength I-Wavelength O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation O B-Citation I-Citation I-Citation I-Citation O B-Citation I-Citation I-Citation I-Citation O O B-Wavelength O B-Wavelength O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Wavelength O O O B-CelestialObject I-CelestialObject O O O O O O O O O O O O O O B-Wavelength O O O O O O O O B-Citation O B-CelestialObject I-CelestialObject O O O O O O O O O O O O O B-Telescope O O O O O O O O O O O O B-Wavelength O O B-Wavelength I-Wavelength O O O O O O O O O O O B-Wavelength B-Wavelength B-Wavelength O O B-Wavelength I-Wavelength O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O
tokens: to a time-span of 3.7 yr). The magnitude difference is only 0.08 mag, which is within the combined photometric error (0.11 mag). We also find that the I -band magnitude at t = 586 d is consistent with the extrapolation of SN 2014C’s earlier MMT light curve. Thus, it is possible that SN 2014C has faded significantly in the I band by t = 586 d, after which the light from Cluster A dominates the I -band brightness. We also note that the emission lines in the I band are much weaker than those in the B, V , and R bands ( M15 ; Anderson et al. 2017 ). To be conservative, however, we do not exclude the possibility that the SN was still bright in the I band and we regard the measured F814W brightness as an upper limit for Cluster A . Similarly, the F336W -band magnitude also remains almost constant from t = 1003 to 1462 d (which corresponds to a time-span of 1.3 yr). The magnitude difference is only 0.06 mag, which is comparable to the combined photometric error (0.05 mag). Note that during the same period, the F555W -band magnitudes faded by 0.17 mag. Yet, SN 2014C, like many other interacting SNe, exhibits a blue pseudo-continuum, which may arise from blended iron lines produced by the ejecta–CSM interaction ( M15 ; see also, e.g. SN 2006jc, Pastorello et al. 2007 ; Bufano et al. 2009 ). As a result, we cannot rule out the possibility that the F336W band is contaminated by the pseudo-continuum emission from the SN. Thus, we regard the F336W -band brightness also as an upper limit for Cluster A . The F275W and F300X bands were only observed at a single epoch. Both bands cover the [Mg ii ] doublets at ∼2800 Å; the F300X band also covers the [Fe ii ] line at ∼2950 Å. These two lines are important coolants and often appear to be very strong in emission for interacting SNe (Fesen et al. 1999 ; Fransson et al. 2005 ; Bufano et al. 2009 ). Thus, F275W and F300X bands may be contaminated by the SN light, although it is difficult to estimate the amount of its contribution. Still, they place important upper limits for the brightness of Cluster A at UV wavelengths. In summary, SN 2014C’s light was still significant until at least 4 yr post-explosion (the last epoch of F555W observation). This is consistent with the conclusion of T19 that SN 2014C experiences ongoing interaction between its ejecta and CSM at large distances. Still, the HST observations provide very important constraints on Cluster A ’s SED from the UV to the F814W band, a much wider wavelength coverage than the pre-explosion observations in the B, V, R , and F658N bands. Thanks to the higher spatial resolution provided by the new data, the measured SED of Cluster A is now much cleaner, i.e. without significant contamination from its nearby sources. 4 PROPERTIES OF THE HOST STAR CLUSTER We further try to infer the properties of Cluster A by fitting model spectra to its observed SED. Note that Cluster A is still associated with a considerable amount of (ionized) gas, given its bright