About me

I am working in Prof. Nicholas Law team at the Department of Physics and Astronomy at the University of North Carolina at Chapel Hill as a Postdoctoral Research Associate since Mar 2014.

In summary, my research spans in the following areas:

  1. Data analysis:
    1. designing and implementing of the Evryscope targeted-mode pipeline,
    2. wavelet-based analysis of light curves,
    3. image fusion,
    4. image deconvolution.
  2. Instrumentation:
    1. designing and building robotic telescopes,
    2. designing and implementing of new high-speed reading modes for CCD and NIR imagers.
  3. Science:
    1. surveying transiting planetesimals around white dwarfs, and transiting exoplanets around bright M-dwarfs and nearby bright stars, taking advantage of 1.A and 2.A,
    2. high-angular resolution for new close binaries detection, stellar diameters, and circumstellar shells measurements by means of lunar occultations technique, as an application of 1.B and 2.B.

Research interests

  • Instrumentation in the context of designing and building wide-field robotic telescopes:

1) The Evryscope: a new concept of giga-pixel scale all-sky 10,200 deg² telescope. The first prototype was deployed at CTIO on May 2015. The Evryscope concept consists on a 27x(7-cm wide field lenses + CCDs) multiplexed telescope.

The Evryscope concept.

At the moment 23 cameras are installed, exposing at a 2-minute cadence, and a limiting magnitude down to g=16.5mag (3-σ) for that exposure time.

Deployment images at CTIO:

My role in the instrumentation side of the Evryscope is focused on the definition and implementation of the CCD filters, observatory facilities such as high performance computing, relational database and storage units, LAN and power distribution network, and a large number of tiny details I learned from previous robotic telescopes projects I lead/participated (e.g. see 2) which they are useful for the Evryscope.

Field of view of Evryscope:

See below the instantaneous full Evryscope image, stitched together from all cameras

evryscope_full_image_2A zoom into the white box in the image above:

evryscope_1_imageThe Evryscope has been profiled in several journals such as Science, Science News, and Sky & Telescope.

Most relevant pubs: Fors et al. (2015b), Fors et al. (2015c), Law et al. (2015c), Law et al. (2015b), Law et al. (2015a)Ratzloff et al. (2015), Wulfken et al. (2015), Law et al. (2014).

Evryscope-North construction begins:

We have started ordering the parts for a Northern Evryscope to be deployed at the Mount Laguna Observatory (MLO). The Evryscope-North is funded by a collaboration of San Diego State University (SDSU), UNC-Chapel Hill  and the Research Corporation Scialog program. See more details in here.

2) Telescope Fabra ROA Montsec (TFRM): since Jun 2006 I was on charge of design, development, and deployment of the refurbishment project of the 50cm f/0.96 Baker-Nunn Camera for the automatic use of a 4.4°x4.4° CCD in the Catalan Pre-Pyrenees.

Most relevant pubs: Fors et al. (2013), Muiños et al. (2012), Fors et al. (2011), Montojo et al. (2011), Fors et al. (2010a), Fors et al. (2010b).

  • Transiting exoplanets surveys:

1) Given the all-sky minute-cadence of Evryscope, this is a unique facility to tackle a diverse plethora of observational programs. In the area of the transiting exoplanets, there are three detection subprograms which are being conducted thanks to the milimagnitude precision delivered light curves:

  1.1) to first-time detect Ceres-size rocky objects around bright white dwarfs. Evryscope will monitor ~1,000 white dwarfs brighter than g=16mag at a minute cadence.

  1.2) TESS precursor observations. The Evryscope will provide long-term monitoring of TESS targets, measuring stellar activity and vetting for variable stars. The system will also increase the TESS giant planet yield by recovering multiple transits from objects seen as single eclipses in the relatively short TESS search period.

  1.3) as Kepler populations statistics, ~5-10 few-Earth-radii rocky planets in habitable zone are likely to be detected in the ~5,000 bright M-dwarfs accessible to the Evryscope. ~100,000 M-dwarfs are searchable for giants planets.

  1.4) to increase the number of giant planets known around ~70,000 nearby stars brighter than V=9mag. With follow up observations, the atmospheric characterization of such population of planets will be improved.

2) TFRM-PreSelected Super-Earths Survey (TFRM-PSES): the TFRM 19.4-square-degree FoV is its most remarkable feature. This, combined with the fact that a 30-second exposure typically contains ~20.000 stars with SNR>5 (V<15.5mag) and a photometric precision better than 10 milimagnitudes (3-4 milimagmitudes typically for V down to 13-13.5mag), makes that the telescope has a significant probability in detecting new transiting exoplanets.

Since Dec 2011, I lead a survey, called TFRM-PSES, of a pre-selected series of fields, with an input catalog similar to MEarth’s, in search of super-Earths around Ms dwarfs. The TFRM-PSES has a 35sec cadence, sufficient for sampling a typical transiting periods of super-Earths in the habitable zone around Ms dwarfs. The survey monitors multiple fields observed every night, each one simultaneously containing typically ~20 M-type cataloged stars, mainly in the range of 9.0mag<V<15.5mag.

Most relevant pubs: del Ser et al. (2014), Fors et al. (2013), Fors et al. (2012), Fors et al. (2010a).

  • NIR and visible high angular resolution using high-speed photometry by means of stellar lunar occultations (LO):

1) development and results of drift-scanning technique to use CCD sensors for observing LO (temporal resolution ~ 2 milliseconds). Results of new binaries detections with projected separations ~ [2-20]mas, obtained with Celestron 14in. (Fabra Observatory) and 1.52m-OAN telescopes (Calar Alto Observatory).

Most relevant pubs: Fors et al. (2004a), Fors et al. (2004b), Fors et al. (2001)

2) extension of stellar LO observations using ~8-millisecond photometry and ~3-millisecond photometry with the two venerable NIR arrays: MAGIC @ Calar Alto Observatory and the (already decommissioned) ISAAC @ the VLT, respectively.

Fresnel diffraction fringes are incorporated into the stellar light curve as the Moon occults the source in a timescale of ~0.1s. High angular information of the source is embedded in the diffraction fringes.

Example of VLT/ISAAC camera @ burst mode, detecting a very close (Θ=0.4mas) and faint (K=8.28) companion of IRAS 17529-2830.

Most relevant pubs: Richichi et al. (2014), Richichi et al. (2013), Richichi et al. (2012a), Richichi et al. (2012b), Richichi et al. (2011), Richichi et al. (2010), Richichi et al. (2009), Richichi et al. (2008a), Richichi et al. (2008b), Richichi et al. (2006b), Fors et al. (2006), Richichi et al. (2006a), Fors et al. (2004)

  • Data analysis:

1) The Evryscope will produce a data flow of 0.8Gb/min, which constitutes a challenge in terms of data analysis. I am leading the development of EvryPipe-I, a targeted-mode (for a selected list of targets) version of the Evryscope data reduction pipeline.

As a benchmark for developing EvryPipe-I, I am currently reducing High Canadian Arctic Wide-field Cameras (AWCam) survey, which in terms of data flow, pixel sampling, and limiting magnitude resembles to Evryscope situation. AWCams are two very-wide field cameras located at +80° latitude, on Ellesmere Island in the High Canadian Arctic. They monitor ∼70,000 bright stars in a several-hundred square-degree region around Polaris, with milli-magnitude photometric precision, in the search of giant planets around ∼10,000 bright, nearby solar-type stars.

Most relevant pubs: Fors et al. (2015a), Law et al. (2014).

2) Automatic analysis of LO light curves by means of wavelet transform. Design, development and implementation of AWLORP (Automatic Wavelet-based Lunar Occultation Reduction Package).

Most relevant pubs: Fors et al. (2008), Fors (2006).

3) Wavelet transform-based method for the determination of the relative resolution between remotely sensed images.

Most relevant pubs: Nunez et al. (2006).

5) Wavelet transform-based image deconvolution applied for improving limiting magnitude and angular resolution of different types of surveys:

Yale QUasar Equatorial Survey Team (QUEST) @ CIDA (Venezuela).

USNO Flagstaff Astrometric Scanning Transit Telescope (FASTT).

Univ. of Calgary Baker-Nunn Camera: the terrestrial counterpart of the Near-Earth Space Surveillance (NESS) satellite.

USAF Phoenix Baker-Nunn Camera: improvement of detection of faint stars and moving objects with image deconvolution.

Most relevant pubs: Fors et al. (2010), Fors et al. (2006), Merino et al. (2006), Fors (2006).

Upcoming science with Evryscope:

Evryscope is a unique facility to tackle a plethora of observational programs such as transiting exoplanets, eclipsing binaries, microlensing, young stars, nearby SNs, GRBs, optical counterparts of gravitational waves detections, and high (gamma and X-ray) and low (radio) energy transients.

As all images are stored and due to its minute cadence, perhaps the most valuable and unique capability of The Evryscope is to enable to study not only the post facto transient light curve, but also the pre transient light curve of such object within the desired time-frame (The Evryscope has no pointing overheads, the only constraint is daytime window).

Most relevant pubs: Fors et al. (2015b), Fors et al. (2015c), Law et al. (2015b), Law et al. (2015c).