The Hubble Space Telescope Extragalactic Distance Scale Key Project. 1: The discovery of Cepheids and a new distance to M81

Freedman, Wendy L.; Hughes, Shaun M. G.; Madore, Barry F.; Mould, Jeremy; Lee, Myung Gyoon; Stetson, P. B.; Kennicutt, Robert C.; Turner, Anne Marie Stewart; Ferrarese, Laura; Ford, H. C.; Graham, J. A.; Hill, Robert J.; Hoessel, John G.; Huchra, J. P.; Illingworth, G. D.

doi:10.1086/174172

Cited by 523 publications

(459 citation statements)

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“…Radiation hydrodynamics models of the light curve suggest that the ejected M Ni56 is 0.06-0.09 M  (Shigeyama et al 1994;Woosley et al 1994), based on a distance to M81 of 3.3 Mpc. With the M81 distance revised to 3.63 Mpc (Freedman et al 1994), this estimate becomes 0.07-0.11 M  . Luminosity constraints and estimates of the ejected mass based on light curve modeling indicate M 12 ZAMS » -17 M  (Shigeyama et al 1994;Woosley et al 1994;Young et al 1995).…”

Section: Observational Samplementioning

confidence: 99%

The Development of Explosions in Axisymmetric Ab Initio Core-Collapse Supernova Simulations of 12–25 Stars

Bruenn

Lentz

Hix

et al. 2016

ApJ

204

300

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We present four ab initio axisymmetric core-collapse supernova simulations initiated from 12, 15, 20, and 25 M  zero-age main sequence progenitors. All of the simulations yield explosions and havebeen evolved for at least 1.2 s after core bounce and 1 s after material first becomes unbound. These simulations were computed with our CHIMERA code employing RbR spectral neutrino transport, special and general relativistic transport effects, and state-of-the-art neutrino interactions. Continuing the evolution beyond 1 s after core bounce allows the explosions to develop more fully and the processes involved in powering the explosions to become more clearly evident. We compute explosion energy estimates, including the negative gravitational binding energy of the stellar envelope outside the expanding shock, of 0.34, 0.88, 0.38, and 0.70 Bethe (B≡10 51 erg) and increasing at 0.03, 0.15, 0.19, and 0.52 B s 1 -, respectively, for the 12, 15, 20, and 25 M  models at the endpoint of this report. We examine the growth of the explosion energy in our models through detailed analyses of the energy sources and flows. We discuss how the explosion energies may be subject to stochastic variations as exemplfied by the effect of the explosion geometry of the 20 M  model in reducing its explosion energy. We compute the proto-neutron star masses and kick velocities. We compare our results for the explosion energies and ejected Ni 56 masses against some observational standards despite the large error bars in both models and observations.

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Section: Observational Samplementioning

confidence: 99%

The Development of Explosions in Axisymmetric Ab Initio Core-Collapse Supernova Simulations of 12–25 Stars

Bruenn

Lentz

Hix

et al. 2016

ApJ

204

300

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“…Since we know the distance to M 81* (3.63 Mpc; Freedman et al 1994), we can compute the normalized core shift on a linear scale: Ω ∼ 0.031 pc GHz. This value can be used (together with the distances from the cores to the central engine of the AGN, reported in the previous subsection) to estimate the magnetic field in the jet assuming particle-field energy equipartition (see, e.g., Eq.…”

Section: Magnetic Field In the Jet And Black-hole Massmentioning

confidence: 99%

“…The galaxy M 81 (NGC 3031), located at a distance of 3.63 ± 0.34 Mpc (Freedman et al 1994), hosts the next closest active galactic nucleus (AGN) after Centaurus A. Its high declination (J2000.0 coordinates α = 09 h 55 m 33.173 s and δ = 69 • 03 55.062 ) also makes M 81 a perfect target for global VLBI observations using the most sensitive radio telescopes in the Northern Hemisphere.…”

Section: Introductionmentioning

confidence: 99%

Detection of jet precession in the active nucleus of M 81

Martí-Vidal

Marcaide

Alberdi

et al. 2011

A&A

105

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We report on very-long-baseline-interferometry (VLBI) monitoring observations of the low-luminosity active galactic nucleus (LLAGN) in the galaxy M 81 at the frequencies of 1.7, 2.3, 5.0, and 8.4 GHz. The observations reported here are phase-referenced to the supernova SN 1993J (located in the same galaxy) and cover from late 1993 to late 2005. The large amount of available observations allows us to study the stability of the AGN position in the frame of its host galaxy at different frequencies and chromatic effects in the jet morphology, together with their time evolution. The source consists at all frequencies of a slightly resolved core and a small jet extension towards the northeast direction (position angle of ∼65 degrees) in agreement with previous publications. We find that the position of the intensity peak in the images at 8.4 GHz is very stable in the galactic frame of M 81 (proper motion upper limit about 10 μas per year). We confirm previous reports that the peaks at all frequencies are systematically shifted among them, possibly due to opacity effects in the jet as predicted by the standard relativistic jet model. We use this model, under plausible assumptions, to estimate the magnetic field in the jet close to the jet base and the mass of the central black hole. We obtain a black-hole mass of ∼2 × 10 7 M , comparable to estimates previously reported using different approaches, but the magnetic fields obtained are 10 3 −10 4 times lower than previous estimates. We find that the positions of the cores at 1.7, 2.3, and 5.0 GHz are less stable than that at 8.4 GHz and evolve systematically, shifting southward at a rate of several tens of μas per year. The evolution in the jet orientation seems to be related to changes in the inclination of the cores at all frequencies. These results can be interpreted as due to a precessing jet. The evolving jet orientation also seems to be related to a flare in the peak flux densities at 5.0 and 8.4 GHz, which lasts ∼4 years (from mid 1997 to mid 2001). An increase in the accretion rate of the black hole, and its correlation with the jet luminosity via the disk-jet connection model, seems insufficient to explain this long flare and the simultaneous evolution in the jet orientation. A continued monitoring of the flux density and the jet structure evolution in this LLAGN will be necessary to further confirm our jet precession model.

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“…The total reddening in M81 (foreground plus M81 contribution) has been measured by a number of authors (e.g., Freedman et al 1994;Kong et al 2000). We only mention here that Kong et al (2000) obtained the reddening maps of M81 based on the images in 13 intermediate-band filters from 3800 to 10000 Å .…”

Section: Reddeningmentioning

confidence: 99%

Color and Metallicity Distributions of M81 Globular Clusters

Zhou

Chen

et al. 2005

PUBL ASTRON SOC PAC

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ABSTRACT. In this paper we present catalogs of photometric and spectroscopic data for globular clusters (GCs) in M81. The catalogs include B-and V-band photometric and reddening data of 95 GCs, in addition to spectroscopic metallicities of 40 GCs. Using these data, we make some statistical correlations. The results show that the distributions of intrinsic B and V colors and metallicities are bimodal, with metallicity peaks at and Ϫ0.53, respectively, as has been demonstrated for our Milky Way and M31. The relation [Fe/H] ≈ Ϫ1.45 between spectroscopic metallicity and intrinsic B and V color also exists as it does for the Milky Way and M31.

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The Hubble Space Telescope Extragalactic Distance Scale Key Project. 1: The discovery of Cepheids and a new distance to M81

Cited by 523 publications

References 0 publications

The Development of Explosions in Axisymmetric Ab Initio Core-Collapse Supernova Simulations of 12–25 Stars

The Development of Explosions in Axisymmetric Ab Initio Core-Collapse Supernova Simulations of 12–25 Stars

Detection of jet precession in the active nucleus of M 81

Color and Metallicity Distributions of M81 Globular Clusters

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