The brightness of magnetic field concentrations in the quiet Sun
arXiv:1010.4792 · doi:10.1051/0004-6361/201015976
Abstract
In addition to the `facular' brightening of active regions, the quiet Sun also contains a small scale magnetic field with associated brightenings in continuum radiation. We measure this contribution of quiet regions to the Sun's brightness from high spatial resolution (0"16-0"32) observations of the Swedish 1-m Solar Telescope (SST) and Hinode satellite. The line-of-sight magnetic field and continuum intensity near \ion{Fe}{i} 6302.5 Å are used to quantify the correlation between field strength and brightness. The data show that magnetic flux density contains a significant amount of intrinsically weak fields that contribute little to brightness. We show that with data of high spatial resolution a calibration of magnetic flux density as a proxy for brightness excess is possible. In the SST data, the magnetic brightening of a quiet region with an average (unsigned) flux density of 10 G is about 0.15%. In the Hinode data, and in SST data reduced to Hinode resolution, the measured brightening is some 40% lower. With appropriate correction for resolution, magnetic flux density can be used as a reliable proxy in regions of small scale mixed polarity. The measured brightness effect is larger than the variation of irradiance over a solar cycle. It is not clear, however, if this quiet Sun contribution actually varies significantly. \keywords{Sun: surface magnetism -- photosphere -- solar-terrestrial relations}
arXiv commentA&A (in press)
References in corpus (12)
- CRISP Spectropolarimetric Imaging of Penumbral Fine Structure
- A Substantial Amount of Hidden Magnetic Energy in the Quiet Sun
- Observational manifestations of solar magneto-convection -- center-to-limb variation
- Strong horizontal photospheric magnetic field in a surface dynamo simulation
- Point spread functions for the Solar Optical Telescope onboard Hinode
- Turbulent magnetic fields in the quiet Sun: implications of Hinode observations and small-scale dynamo simulations
- Magnetic bright points in the quiet Sun
- Stray light correction and contrast analysis of Hinode broad band images
- Dimming of the 17th Century Sun
- Intensity contrast from MHD simulations and from HINODE observations
- The intensity contrast of solar photospheric faculae and network elements II. Evolution over the rising phase of solar cycle 23
- Modeling Total Solar Irradiance Variations Using Automated Classification Software On Mount Wilson Data
Cited by in corpus (22)
- Critical Science Plan for the Daniel K. Inouye Solar Telescope (DKIST)
- Solar cycle variation in solar irradiance
- Intensity contrast of solar network and faculae
- Solar magnetoconvection and small-scale dynamo: Recent developments in observation and simulation
- Point spread function of SDO/HMI and the effects of stray light correction on the apparent properties of solar surface phenomena
- Brightness of Solar Magnetic Elements as a Function of Magnetic Flux at High Spatial Resolution
- Solar Irradiance Variability
- Comparison of physical properties of quiet and active regions through the analysis of MHD simulations of the solar photosphere
- Total Solar Irradiance during the Last Five Centuries
- Photometric Properties of Network and Faculae Derived from HMI Data Compensated for Scattered-Light
- The continuum intensity as a function of magnetic field II. Local magnetic flux and convective flows
- A comparison between solar plage and network properties
- Small-scale dynamos on the solar surface: dependence on magnetic Prandtl number
- Intensity contrast of solar plage as a function of magnetic flux at high spatial resolution
- The dark side of solar photospheric G-band bright points
- The cross helicity at the solar surface by simulations and observations
- Center-to-limb variation of the area covered by magnetic bright points in the quiet Sun
- Intensity contrast of solar network and faculae -- II. Implications for solar irradiance modelling
- Brightness of the Sun's small scale magnetic field: proximity effects
- Analysis and modeling of solar irradiance variations
- Can Rossby waves explain the cyclic magnetic activity of the Sun and solar-type stars?
- On the global magnetic activity and dynamo of the Sun and solar-type stars