The Astrophysical Journal Letters is a peer-reviewed express scientific journal that allows astrophysicists to rapidly publish short notices of significant original research. The American Astronomical Society has chosen IOP Publishing to publish The Astrophysical Journal.
Number 1, 2014 August 10 (L1-L18)
The American Astronomical Society (AAS) and IOP Publishing (IOP) have decided that all AAS research journals published with IOP will become electronic only and will no longer print paper editions.
Our online author services system makes it easy to submit an article to the ApJL. All you need to do is upload and approve your manuscript and the peer-review process will start immediately.
The Astrophysical Journal is the leading international research journal in its field and publishes papers across the breadth of astronomy and astrophysics.
Submit an article to the ApJ.
The Astrophysical Journal Supplement publishes significant papers containing extensive data or calculations, or of very specialized interest. The Supplement contains many of the most frequently cited papers in the astronomical literature.
Submit an article to the ApJ Supplement.
These are the latest articles published in The Astrophysical Journal Letters.
R. M. González Delgado et al. 2014 ApJ 791 L16
We use spatially and temporally resolved maps of stellar population properties of 300 galaxies from the CALIFA integral field survey to investigate how the stellar metallicity ( Z ) relates to the total stellar mass ( M ) and the local mass surface density (μ ) in both spheroidal- and disk-dominated galaxies. The galaxies are shown to follow a clear stellar mass-metallicity relation (MZR) over the whole 10 9-10 12 M ☉ range. This relation is steeper than the one derived from nebular abundances, which is similar to the flatter stellar MZR derived when we consider only young stars. We also find a strong relation between the local values of μ and Z (the μZR), betraying the influence of local factors in determining Z . This shows that both local (μ -driven) and global ( M -driven) processes are important in determining metallicity in galaxies. We find that the overall balance between local and global effects varies with the location within a galaxy. In disks, μ regulates Z , producing a strong μZR whose amplitude is modulated by M . In spheroids it is M that dominates the physics of star formation and chemical enrichment, with μ playing a minor, secondary role. These findings agree with our previous analysis of the star formation histories of CALIFA galaxies, which showed that mean stellar ages are mainly governed by surface density in galaxy disks and by total mass in spheroids.
Thomas E. Harrison 2014 ApJ 791 L18
The WISE mission happened to observe the cataclysmic variable Z Cam at the peak of an outburst. The WISE single exposure data shows that Z Cam was highly variable at 12 μm, but only marginally so at shorter wavelengths. The rapid variability at 12 μm, and the fact that these observations occurred close to visual maximum suggests that, like SS Cyg, Z Cam is a synchrotron source.
S. L. Snowden et al. 2014 ApJ 791 L14
Three recent results related to the heliosphere and the local interstellar medium (ISM) have provided an improved insight into the distribution and conditions of material in the solar neighborhood. These are the measurement of the magnetic field outside of the heliosphere by Voyager 1, the improved mapping of the three-dimensional structure of neutral material surrounding the Local Cavity using extensive ISM absorption line and reddening data, and a sounding rocket flight which observed the heliospheric helium focusing cone in X-rays and provided a robust estimate of the contribution of solar wind charge exchange emission to the ROSAT All-Sky Survey 1/4 keV band data. Combining these disparate results, we show that the thermal pressure of the plasma in the Local Hot Bubble (LHB) is P/ k = 10, 700 cm –3 K. If the LHB is relatively free of a global magnetic field, it can easily be in pressure (thermal plus magnetic field) equilibrium with the local interstellar clouds, eliminating a long-standing discrepancy in models of the local ISM.
P. Privitera and P. Motloch 2014 ApJ 791 L15
In a recent Letter, Jupiter is presented as an efficient detector for Ultra-High Energy Cosmic Rays (UHECRs), through measurement by an Earth-orbiting satellite of gamma rays from UHECRs showers produced in Jupiter's atmosphere. We show that this result is incorrect, due to erroneous assumptions on the angular distribution of shower particles. We evaluated other solar system objects as potential targets for UHECRs detection, and found that the proposed technique is either not viable or not competitive with traditional ground-based UHECRs detectors.
M. P. Pulupa et al. 2014 ApJ 791 L17
We present observational evidence of core electron heating in solar wind reconnection exhausts. We show two example events, one which shows clear heating of the core electrons within the exhaust, and one which demonstrates no heating. The event with heating occurred during a period of high inflow Alfvén speed ( V A L ), while the event with no heating had a low V A L . This agrees with the results of a recent study of magnetopause exhausts, and suggests that similar core electron heating can occur in both symmetric (solar wind) and asymmetric (magnetopause) exhausts.