Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · 0802.4446

Holmberg Ix: The Nearest Young Galaxy

E. Sabbi·J. S. Gallagher·L. J. Smith·D. F. de Mello·M. Mountain
View original source ↗Read source document ↗Export metadata ↓

Abstract

Deep images taken with the Wide Field Channel of the Advanced Camera for Surveys on board the Hubble Space Telescope provide the basis for study the resolved stellar population of the M81 companion dwarf irregular galaxy Holmberg IX. Based on color-magnitude diagrams the stellar population toward Holmberg IX contains numerous stars with ages of <~200 Myr as well as older red giant stars. By charting the spatial distribution of the red giant stars and considering their inferred metallicities, we concluded that most of these older stars are associated with M81 or its tidal debris. At least 20% of the stellar mass in Holmberg IX was produced in the last ~200 Myr, giving it the youngest stellar populations if any nearby galaxy. The location of Holmberg IX, its high gas content, and its youthful stellar population suggests that it is a tidal dwarf galaxy, perhaps formed during the last close passage of M82 around M81.

Explore related subjects

astro-ph

Keep this discovery

BibTeXRIS

E. Sabbi, J. S. Gallagher, L. J. Smith, D. F. de Mello, M. Mountain. 2008-02-29. Holmberg Ix: The Nearest Young Galaxy. https://doi.org/10.1086/587548

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2018

Putting The Together A Cyclical Baryonic Universe

There are multiple examples of gravitational losses in neutron stars and black holes. Protons and neutrons have been found to have enormous repulsive pressures that highly squeezed collapsing matter cannot overcome. The case against singularities follows. Galactic black hole gravitational losses can supply the missing dark energy. With highly squeezed nucleons, the big bang could begin as a hot core and a cold dark matter shell. The 21 cm. radiation data has identified baryon sized particles as cold dark matter. Highly squeezed nucleons will not decompose to produce antimatter. The flatness of the Universe is due to a baryonic bounce. The highly correlated galaxies originated from primordial black holes capturing hot core gasses.There is evidence that galaxies have not grown nor merged significantly since formation.

astro-ph↗
arXiv2018

Direct observation of high-speed plasma outflows produced by magnetic reconnection in solar impulsive events

Spectroscopic observations of a solar limb flare recorded by SUMER on SOHO reveal, for the first time, hot fast magnetic reconnection outflows in the corona. As the reconnection site rises across the SUMER spectrometer slit, significant blue- and red-shift signatures are observed in sequence in the Fe XIX line, reflecting upflows and downflows of hot plasma jets, respectively. With the projection effect corrected, the measured outflow speed is between 900-3500 km/s, consistent with theoretical predictions of the Alfvenic outflows in magnetic reconnection region in solar impulsive events. Based on theoretic models, the magnetic field strength near the reconnection region is estimated to be 19-37 Gauss.

astro-ph↗
arXiv2018

Multiwavelength evidence of the physical processes in radio jets

Over the last few years, high-quality X-ray imaging and spectroscopic data from Chandra and XMM-Newton have added greatly to the understanding of the physics of radio jets. Here we describe the current state of knowledge with an emphasis on the underlying physics used to interpret multiwavelength data in terms of physical parameters.

astro-ph↗