RT Journal Article
T1 Once in a blue stream : detection of recent star formation in the NGC 7241 stellar stream with MEGARA
A1 Martínez-Delgado, David
A1 Roca Fábrega, Santi
A1 Gil De Paz, Armando
A1 Miró-Carretero, Juan
A1 Gómez Flechoso, María De Los Ángeles
A1 Gallego Maestro, Jesús
A1 Pascual Ramírez, Sergio
A1 Cardiel López, Nicolás
A1 Castillo Morales, María África
A1 Gómez-Alvarez, Pedro
AB Aims. In this work we study the striking case of a narrow blue stream with a possible globular cluster-like progenitor around the NGC 7241 galaxy and its foreground dwarf companion. We want to figure out if the stream was generated by tidal interaction with NGC 7241 or if it first interacted with the foreground dwarf companion and later both fell together toward NGC 7241.Methods. We used four sets of observations, including a follow-up spectroscopic study of this stream based on data taken with the MEGARA instrument at the 10.4 m Gran Telescopio Canarias using the integral field spectroscopy mode, the Mount Lemmon 0.80m telescope, the Telescopio Nazionale Galileo, the DESI Imaging Legacy surveys, and GALEX archival data. We also used high-resolution zoomed-in cosmological simulations.Results. Our data suggest that the compact object we detected in the stream is a foreground Milky Way halo star. Near this compact object we detect emission lines overlapping a less compact, bluer, and fainter blob of the stream that is clearly visible in both ultraviolet and optical deep images. From its heliocentric systemic radial velocity derived from the [O III]lambda 5007 angstrom lines (V-syst = 1548.58 +/- 1.80 km s(-1)) and new UV and optical broadband photometry, we conclude that this overdensity could be the actual core of the stream, with an absolute magnitude of M-g similar to -10 and a g - r = 0.08 +/- 0.11, consistent with a remnant of a low-mass dwarf satellite undergoing a current episode of star formation. From the width of the stream and assuming a circular orbit, we calculate that the progenitor mass can be typical of a dwarf galaxy, but it could also be substantially lower if the stream is on a very radial orbit or if it was created by tidal interaction with the companion dwarf instead of with NGC 7241. These estimates also suggest that this is one of the lowest mass streams detected to date beyond the Local Group. Finally, we find that blue stellar streams containing star formation regions are commonly predicted by high-resolution cosmological simulations of galaxies lighter than the Milky Way. This scenario is consistent with the processes explaining the bursty star formation history of some dwarf satellites, which are followed by a gas depletion and a fast quenching once they enter within the virial radius of their host galaxies for the first time. Thus, it is likely that the stream's progenitor is undergoing a star formation burst comparable to those that have shaped the star formation history of several Local Group dwarfs in the last few gigayears.
PB EDP Sciences
SN 0004-6361
YR 2024
FD 2024-04-17
LK https://hdl.handle.net/20.500.14352/120580
UL https://hdl.handle.net/20.500.14352/120580
LA eng
NO Martínez-Delgado, D.; Roca-Fàbrega, S.; Gil De Paz, A.; Erkal, D.; Miró-Carretero, J.; Makarov, D.; Voggel, K.T.; Leaman, R.; Bolchin, W.; Pearson, S.; et al. Once in a Blue Stream: Detection of Recent Star Formation in the NGC 7241 Stellar Stream with MEGARA. A&A 2024, 684, A157, doi:10.1051/0004-6361/202244350.
NO Artículo firmado por 26 autores
NO Junta de Andalucía
NO Ministerio de Ciencia, Innovación y Universidades (España)
NO Ministerio de Economía y Competitividad (España)
NO Universidad Complutense de Madrid
NO Comunidad de Madrid
NO Gobierno de España
NO Instituto de Salud Carlos III (España)
NO European Union NextGenerationEU
NO Dark Energy Camera Legacy Survey (DECaLS)
NO Beijing-Arizona Sky Survey (BASS; NOAO)
NO Mayall z-band Legacy Survey (MzLS)
NO United States Department of Energy (DOE)
NO National Science Foundation (NSF)
NO UK Research & Innovation (UKRI)
NO Science & Technology Facilities Council (STFC)
NO Higher Education Funding Council for England (HEFCE)
NO National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign
NO German Research Foundation (DFG)
NO University of Cambridge
NO Institut de Ciencies de l'Espai (IEEC/CSIC)
NO Institut de Fisica d'Altes Energies
NO National Aeronautics & Space Administration (NASA)
DS Docta Complutense
RD 20 mar 2026