Using multi-wavelength data, from UV-optical-near-mid IR, for ∼6000 galaxies in the local Universe, we study the dependence of star formation on the morphological Ttypes for massive galaxies (log M * /M ≥ 10). We find that, early-type spirals (Sa-Sbc) and S0s predominate in the green valley, which is a transition zone between the star forming and quenched regions. Within the early-type spirals, as we move from Sa to Sbc spirals the fraction of green valley and quenched galaxies decreases, indicating the important role of the bulge in the quenching of galaxies. The fraction of early-type spirals decreases as we enter the green valley from the blue cloud, which coincides with the increase in the fraction of S0s. This points towards the morphological transformation of early-type spiral galaxies into S0s which can happen due to environmental effects such as ram-pressure stripping, galaxy harassment, or tidal interactions. We also find a second population of S0s which are actively star-forming and are present in all environments. Since morphological T-type, specific star formation rate (sSFR), and environmental density are all correlated with each other, we compute the partial correlation coefficient for each pair of parameters while keeping the third parameter as a control variable. We find that morphology most strongly correlates with sSFR, independent of the environment, while the other two correlations (morphology-density and sSFR-environment) are weaker. Thus, we conclude that, for massive galaxies in the local Universe, the physical processes that shape their morphology are also the ones that determine their star-forming state.

Here we report the discovery with the Giant Metrewave Radio Telescope of an extremely large (∼115 kpc in diameter) Hi ring off-centered from a massive quenched galaxy, AGC 203001. This ring does not have any bright extended optical counterpart, unlike several other known ring galaxies. Our deep g, r, and i optical imaging of the Hi ring, using the MegaCam instrument on the Canada-France-Hawaii Telescope, however, shows several regions with faint optical emission at a surface brightness level of ∼28 mag/arcsec 2 . Such an extended Hi structure is very rare with only one other case known so far -the Leo ring. Conventionally, off-centered rings have been explained by a collision with an "intruder" galaxy leading to expanding density waves of gas and stars in the form of a ring. However, in such a scenario the impact also leads to large amounts of star formation in the ring which is not observed in the ring presented in this paper. We discuss possible scenarios for the formation of such Hi dominated rings.

We have carried out a systematic search for outlying Hα emitters in the entire data release 14 of the Sloan Digital Sky Survey (SDSS) IV Mapping Nearby Galaxies at APO (MaNGA) survey. We have discovered six outlying Hα emitters with no bright underlying optical continuum emission in the imaging data release 5 from the Dark Energy Camera Legacy Survey (DECaLS) and data release 6 of the Mayall z-band Legacy Survey (MzLS) + Beijing-Arizona Sky Survey (BASS). They also show a velocity field which is different from that of the host galaxy. These outlying Hα emitters all have extended structure in the Hα image. Their emission line ratios show that they are photoionised due to an active galactic nucleus (AGN) or a mixture of both an AGN and star formation. Some of them are very likely to be fainter counterparts of Hanny's Voorwerp like objects.