Jianghua Wu - National Astronomical Observatories, Chinese Academy of Sciences, Beijing, China

Jianghua Wu
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Name
Jianghua Wu
Affiliation
National Astronomical Observatories, Chinese Academy of Sciences, Beijing, China
City
Beijing
Country
China

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Cosmology and Nongalactic Astrophysics (10)
 
Astrophysics (9)
 
Astrophysics of Galaxies (7)
 
High Energy Astrophysical Phenomena (5)
 
Instrumentation and Methods for Astrophysics (3)

Publications Authored By Jianghua Wu

We have monitored the BL Lacertae object S5 0716+714 simultaneously in the B, R and I bands on three nights in November 2014. The average time resolution is quite high (73s, 34s, 58s for the filters B, R and I), which can help us trace the profile of the variation and search for the short inter-band time delay. Intra-day variability was about 0. Read More

2014Nov
Affiliations: 1Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing, China

This paper presents CCD multicolor photometry for 304 old star clusters in the nearby spiral galaxy M31. Of which photometry of 55 star clusters is first obtained. The observations were carried out as a part of the Beijing--Arizona--Taiwan--Connecticut (BATC) Multicolor Sky Survey from 1995 February to 2008 March, using 15 intermediate-band filters covering 3000--10000 \AA. Read More

We present the results of the first systematic long-term multi-color optical monitoring of the BL Lacertae object 1ES 0806+52.4. The monitoring was performed in multiple passbands with a 60/90 cm Schmidt telescope from December 2005 to February 2011. Read More

3C 66A was monitored by the BATC(Beijing-Arizona-Taipei-Connecticut) telescope from 2005 to 2008,1994 observations were obtained on 89 nights. Detailed research and analysis was performed on these observations in this paper. A long term burst occurred in the whole light curve. Read More

We have monitored the BL Lac object S5 0716+714 in five intermediate optical wavebands from 2004 September to 2011 April. Here we present the data that include 8661 measurements which represents one of the largest databases obtained for an object at optical domain. A simple analysis of the data indicates that the object was active in most time, and intraday variability was frequently observed. Read More

2012Nov
Affiliations: 1National Astronomical Observatories, Chinese Academy of Sciences, Beijing, China, 2National Astronomical Observatories, Chinese Academy of Sciences, Beijing, China, 3National Astronomical Observatories, Chinese Academy of Sciences, Beijing, China, 4National Astronomical Observatories, Chinese Academy of Sciences, Beijing, China, 5National Astronomical Observatories, Chinese Academy of Sciences, Beijing, China, 6Department of Astronomy, Beijing Normal University, Beijing China, 7National Astronomical Observatories, Chinese Academy of Sciences, Beijing, China, 8College of Physical Sciences, University of Chinese Academy of Sciences, Beijing China, 9National Astronomical Observatories, Chinese Academy of Sciences, Beijing, China, 10Department of Physics, Nanjing Normal University, Nanjing, China

In this paper, we presented metal abundance properties of 144 M81 globular clusters. These globulars consist of the largest globular cluster sample in M81 till now. Our main results are: the distribution of metallicities are bimodal, with metallicity peaks at [Fe/H]\sim-1. Read More

We present the results of our optical monitoring of the BL Lac object S5 0716+714 on seven nights in 2006 December. The monitoring was carried out simultaneously at three optical wavelengths with a novel photometric system. The object did not show large-amplitude internight variations during this period. Read More

2011Nov
Affiliations: 1National Astronomical Observatories, Chinese Academy of Sciences, 2National Astronomical Observatories, Chinese Academy of Sciences, 3National Astronomical Observatories, Chinese Academy of Sciences, 4National Astronomical Observatories, Chinese Academy of Sciences, 5National Astronomical Observatories, Chinese Academy of Sciences, 6National Astronomical Observatories, Chinese Academy of Sciences

B514 is a remote M31 globular cluster which locating at a projected distance of R_p~55 kpc. Deep observations with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST) are used to provide the accurate integrated light and star counts of B514. By coupling analysis of the distribution of the integrated light with star counts, we are able to reliably follow the profile of the cluster out to ~40". Read More

The colour behaviour of blazars is a subject of much debate. One argument is that the BL Lac objects show bluer-when-brighter chromatism while the flat-spectrum radio quasars (FSRQs) display redder-when-brighter trend. Base on a 3. Read More

Panchromatic spectral energy distribution (SED) from the ultraviolet (UV), optical to infrared (IR) photometry of NGC 628, combined with the evolutionary stellar population synthesis, is used to derive the spatially resolved age, metallicity and reddening maps. These parameter distributions show that the bulge of this galaxy is a disk-like pseudobulge, which has the S{\'e}rsic index close to the exponential law, rich gas, and a young circumnuclear ring structure. We also discover the disk has two distinct regions with different radial age and metallicity gradients. Read More

2011Jan
Affiliations: 1National Astronomical Observatories, Chinese Academy of Sciences, 2National Astronomical Observatories, Chinese Academy of Sciences, 3National Astronomical Observatories, Chinese Academy of Sciences, 4National Astronomical Observatories, Chinese Academy of Sciences, 5National Astronomical Observatories, Chinese Academy of Sciences, 6National Astronomical Observatories, Chinese Academy of Sciences, 7National Astronomical Observatories, Chinese Academy of Sciences

VDB0-B195D is a massive, blue star cluster in M31. It was observed as part of the Beijing-Arizona-Taiwan-Connecticut (BATC) Multicolor Sky Survey using 15 intermediate-band filters covering a wavelength range of 3000--10,000 \AA. Based on aperture photometry, we obtain its spectral-energy distribution (SED) as defined by the 15 BATC filters. Read More

This paper aims to study the color behavior of the BL Lac object OJ 287 during optical outburst. According to the revisit of the data from the OJ-94 monitoring project and the analysis the data obtained with the 60/90 cm Schmidt Telescope of NAOC, we found a bluer-when-brighter chromatism in this object. The amplitude of variation tends to decrease with the decrease of frequency. Read More

2010Aug
Affiliations: 1National Astronomical Observatories, Chinese Academy of Sciences, 2National Astronomical Observatories, Chinese Academy of Sciences, 3National Astronomical Observatories, Chinese Academy of Sciences, 4National Astronomical Observatories, Chinese Academy of Sciences, 5National Astronomical Observatories, Chinese Academy of Sciences, 6National Astronomical Observatories, Chinese Academy of Sciences, 7National Astronomical Observatories, Chinese Academy of Sciences, 8National Astronomical Observatories, Chinese Academy of Sciences

M31 globular cluster B379 is the first extragalactic cluster, the age of which was determined by main-sequence photometry. In this method, the age of a cluster is obtained by fitting its CMD with stellar evolutionary models. However, different stellar evolutionary models use different parameters of stellar evolution, such as range of stellar masses, different opacities and equations of state, and different recipes, and so on. Read More

The Chinese Small Telescope ARray (hereinafter CSTAR) is the first Chinese astronomical instrument on the Antarctic ice cap. The low temperature and low pressure testing of the data acquisition system was carried out in a laboratory refrigerator and on the 4500m Pamirs high plateau, respectively. The results from the final four nights of test observations demonstrated that CSTAR was ready for operation at Dome A, Antarctica. Read More

In 2008 January the 24th Chinese expedition team successfully deployed the Chinese Small Telescope ARray (CSTAR) to DomeA, the highest point on the Antarctic plateau. CSTAR consists of four 14.5cm optical telescopes, each with a different filter (g, r, i and open) and has a 4. Read More

The i-band observing conditions at Dome A on the Antarctic plateau have been investigated using data acquired during 2008 with the Chinese Small Telescope ARray. The sky brightness, variations in atmospheric transparency, cloud cover, and the presence of aurorae are obtained from these images. The median sky brightness of moonless clear nights is 20. Read More

2009Apr
Affiliations: 1National Astronomical Observatories, Chinese Academy of Sciences;, 2National Astronomical Observatories, Chinese Academy of Sciences;, 3Department of Physics & Astronomy, The University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, UK, 4National Astronomical Observatories, Chinese Academy of Sciences;, 5National Astronomical Observatories, Chinese Academy of Sciences;, 6National Astronomical Observatories, Chinese Academy of Sciences;

This paper supplements Jiang et al. (2003), who studied 172 M31 globular clusters (GCs) and globular cluster candidates from Battistini et al. (1987) on the basis of integrated photometric measurements in the Beijing-Arizona-Taiwan-Connecticut (BATC) photometric system. Read More

The source J 1128+5925 was found recently to show strong intraday variability at radio wavelengths and its radio variability may come from interstellar scintillation. In optical, the object was quiet in our 2007 monitoring session. Here we report the results of our new optical monitoring of this source in 2008. Read More

Very recently, J 1128+5925 was found to show strong intraday variability at radio wavelengths and may be a new source with annual modulation of the timescale of its radio variability. Therefore, its radio variability can be best explained via interstellar scintillation. Here we present the properties of its optical variability for the first time after a monitoring program in 2007 May. Read More

2007Aug
Affiliations: 1National Astronomical Observatories, Chinese Academy of Sciences, 2Department of Physics and Astronomy, Arizona State University, Tempe, AZ
Category: Astrophysics

This paper is the third in the series of papers on M81 globular clusters. In this paper, we present spatial and metal abundance properties of 95 M81 globular clusters, which comprise nearly half of all the M81 globular cluster system. These globular clusters are divided into two M81 metallicity groups by a KMM test. Read More

2006Dec
Affiliations: 1National Astronomical Observatories, Chinese Academy of Sciences;, 2National Astronomical Observatories, Chinese Academy of Sciences;, 3Department of Physics and Astronomy, Arizona State University, 4National Astronomical Observatories, Chinese Academy of Sciences;, 5National Astronomical Observatories, Chinese Academy of Sciences;, 6National Astronomical Observatories, Chinese Academy of Sciences;, 7National Astronomical Observatories, Chinese Academy of Sciences;
Category: Astrophysics

We have constrained the age of the globular cluster S312 in the Andromeda galaxy (M31) by comparing its multicolor photometry with theoretical stellar population synthesis models. This is both a check on the age of this globular cluster, as well a check on our methodology. Main-sequence photometry has been the most direct method for determining the age of a star cluster. Read More

We at first introduce a novel photometric system, which consists of a Schmidt telescope, an objective prism, a CCD camera, and, especially, a multi-peak interference filter. The multi-peak interference filter enables light in multi passbands to pass through it simultaneously. The light in different passbands is differentially refracted by the objective prism and is focused on the CCD separately, so we have multi "images" for each object on the CCD frames. Read More

We present the results of our optical monitoring of the BL Lacertae object OJ 287 during the first half of 2005. The source did not show large-amplitude variations during this period and was in a relatively quiescent state. A possible period of 40 days was derived from its light curves in three BATC wavebands. Read More

2005Dec
Affiliations: 1National Astronomical Observatories, Chinese Academy of Sciences;, 2Dominion Astrophysical Observatory, Herzberg Institute of Astrophysics, National Research Council, Canada
Category: Astrophysics

037-B327 is of interest because it is both the most luminous and the most highly reddened cluster known in M31. Deep observations with the Advanced Camera for Surveys on the Hubble Space Telescope provide photometric data in the F606W band, and also show that this cluster is crossed by a dust lane. We determined the structural parameters of 037-B327 by fitting the observed surface brightness distribution to a King model with r_c=0. Read More

2005Dec
Affiliations: 1National Astronomical Observatories, Chinese Academy of Sciences, 2Department of Physics and Astronomy, Arizona State University, Tempe, AZ, 3Department of Physics and Astronomy, Arizona State University, Tempe, AZ
Category: Astrophysics

In this paper, we give the spectral energy distributions of 42 M81 globular clusters in 13 intermediate-band filters from 4000 to 10000 A, using the CCD images of M81 observed as part of the BATC multicolor survey of the Sky. The BATC multicolor filter system is specifically designed to exclude most of the bright and variable night-sky emission lines including the OH forest. Hence, it can present accurate SEDs of the observed objects. Read More

2005Mar
Affiliations: 1National Astronomical Observatories, Chinese Academy of Sciences, 2National Astronomical Observatories, Chinese Academy of Sciences, 3National Astronomical Observatories, Chinese Academy of Sciences, 4National Astronomical Observatories, Chinese Academy of Sciences, 5National Astronomical Observatories, Chinese Academy of Sciences, 6National Astronomical Observatories, Chinese Academy of Sciences, 7National Astronomical Observatories, Chinese Academy of Sciences
Category: Astrophysics

In this paper we present catalogs of photometric and spectroscopic data for M81 globular clusters (GCs). The catalogs include B- and V- photometric and reddening data of 95 GCs, and spectroscopic metallicities of 40 GCs in M81. Using these data, we make some statistical correlations. Read More

Optical monitoring of S5 0716+714 was performed with a 60/90 Schmidt telescope in 2003 November and December and 2004 January for studying the variability of the object on short timescales. Due to the high brightness of the source we could carry out quasi-simultaneous measurements in three bands with a temporal resolution of about 20 minutes by using one single telescope. Intraday and intranight variations were observed with an overall change of ~0. Read More