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Activity > Lunch Talk

Lunch Talk (2018)

ASIAA Lunch Talk is an institute-wide event allowing ASIAA researchers from different fields to discuss astronomy in a very casual manner. The informal meeting is usually held at lunch time on every Monday. Occasionally visitors are also invited to the lunch talk to share their research and ideas with ASIAA researchers.

    Contact
  • Lunch Talk: Colloquium Committee (talks_replace2@_asiaa.sinica.edu.tw)
  • Tech Lunch Talk: Huang, Yen-Ru (yenruhuang_replace2@_asiaa.sinica.edu.tw)
NEXT Lunch Talk: 2018-06-25 Mon 12:00~13:00 [R1203]
Speaker:I-Non Chiu
Topic:X-ray Observable to Mass Scaling Relations of the SPT-selected Galaxy Clusters at 0.2 < z < 1.5 Observed with the XMM-Newton Telescope
Abstract:In this lunch talk, I will present the state-of-the-art result of the X-ray observable to mass scaling relations based on a sample of galaxy clusters selected by the South Pole Telescope out to redshift 1.5.
No. Time/Place Speaker Topic (Abstract)
download PDF: dowaload talk PDF file
12018-08-06 Mon
12:00~13:00
R1203
Thavisha Dharmawardena
[ASIAA/NCU]
Extended dust emission from nearby Asymptotic Giant Branch stars
Abstract

Asymptotic Giant Branch (AGB) stars in the Milky Way are often overlooked due to difficulties in obtaining distances. Understanding their dust emission properties and mass-loss histories leads to better comprehension of the ISM evolution in the Milky Way, in particular its dust reservoir. Most studies have determined the stellar dust mass using mid-IR emission, but a historic cold dust reservoir from a previous mass-loss phase may remain undetected in the mid-IR, requiring observations at longer wavelengths. We present results of a search for extended dust emission from a diverse sample of AGB stars within 1 kpc. This project is part of the Nearby Evolved Star Survey (NESS), which aims to determine gas and dust return from a volume limited sample of galactic evolved stars. Observations at 450​μm​ and 850​μm​ were carried out using the SCUBA-2 instrument on the JCMT and combined with Herschel PACS observations at 70​μm​ and 160​μm from the MESS survey (Groenewegen et al., 2011; Cox et al., 2012). Using azimuthally-averaged surface brightness profiles we determined extension and percentage flux of the extended component for each source at the four wavelengths. We derived extensions at the 3σ levels greater than ~40'' for majority of the sources at SCUBA-2 850​μm​. The fraction of the flux emitted from the extended region is ~40% at 850​μm​ and ~50% at PACS wavelengths. We report a clear detection of the detached shell of U Ant in both 450​μm​ and 850​μm​. This is the first time this detached shell has been detected in the sub-mm continuum. By fitting a modified black body to four-point SEDs at each radial point we derive the dust temperature, spectral index of emissivity, and column density to probe dust mass-loss history and detect changes in physical properties of dust as a function radius (hence, time). The resulting dust-to-gas ratios are consistent with canonicalvalues. The surface density profiles suggest deviation from constant mass loss in a majority of the sources.

22018-07-25 Wed
12:00~13:00
R1203
Liu, Kuan-Yu
[ASIAA]
TBD
32018-07-23 Mon
12:00~13:00
R1203
Kate Pattle
[NTHU]
42018-07-11 Wed
12:00~13:00
R1203
Wei, Ta-Shun
[ASIAA]
TBD
52018-07-09 Mon
12:00~13:00
R1203
Tsan-Ming Wang
[NCU]
INFLUENCE OF VELOCITY DISPERSIONS ON STAR FORMATION ACTIVITIES IN GALAXIES
Abstract

We investigate the influence of the random velocity of molecular gas on the star forming activities in molecular clouds. It is known that physical states of a molecular cloud, such as temperature and density, will influence the star forming activities in the cloud. Besides, it is believed that local and turbulent motions of the molecules in the cloud might provide a significant amount of pressure against gravitational collapse and might thus prevent or reduce star formation in the cloud. However, the influence of the gas motions on the star formation activities is still poorly understood. We used the Atacama Large Millimeter/submillimeter Array (ALMA) data to obtain 12CO(J=1-0) flux and velocity dispersion, combining with the 3.6 and 8 micron mid-infrared data of the Spitzer Space Telescope to probe the effects of gas motion on star formation activities for several nearby galaxies. From our results we were able to derive a modified Kennicutt-Schmidt law with velocity dispersion as an additional parameter. We found that the higher the velocity dispersion in molecular clouds, the lower the star formation activities.

62018-07-04 Wed
12:00~13:00
R1203
Yen, Sheng-Feng
[ASIAA]
TBD
72018-07-02 Mon
12:00~13:00
R1203
Pei-Ying Hsieh
[ASIAA]
82018-06-25 Mon
12:00~13:00
R1203
I-Non Chiu
[ASIAA]
X-ray Observable to Mass Scaling Relations of the SPT-selected Galaxy Clusters at 0.2 < z < 1.5 Observed with the XMM-Newton Telescope
Abstract

In this lunch talk, I will present the state-of-the-art result of the X-ray observable to mass scaling relations based on a sample of galaxy clusters selected by the South Pole Telescope out to redshift 1.5.

92018-06-13 Wed
12:00~13:00
R1203
Chou, Chueh-Yi
[ASIAA]
Commissioning of pfs metrology camera on Subaru telescope
102018-06-11 Mon
12:00~13:00
R1203
Hsi-An Pan
[ASIAA]
Molecular Gas in Interacting Galaxies
Abstract

Galaxy interactions and mergers are often accompanied by an increase in star formation rate (SFR). Since the properties of the molecular gas are essential for star formation, it is vital to establish whether, and by how much, galaxy interaction affects the molecular gas properties, and that in turn lead to the change in SFR. We investigate the influence of galaxy interactions on global molecular gas properties by studying a sample of 61 interacting galaxies, and compare their gas properties with galaxy-properties-matched control sample (isolated galaxies). We find that SFR, gas mass, and gas fraction are gradually enhanced with respect to the control sample as two galaxies approaching each other, and also enhanced from minor to major mergers. On the other hand, dependence of gas star formation efficiency on merger properties is less obvious. According to our analysis, we conclude that galaxy interaction can modify the molecular gas properties of a galaxy, although the strength of the influence is merger properties dependent. Moreover, on the galaxy-wide scale, the total gas content, but not SFE, plays a more important role in the interaction-triggered SFR.

112018-06-04 Mon
12:00~13:00
R1203
Steven Gibson
[WKU/ASIAA]
Dust SED Mapping of Cold Diffuse Clouds
122018-05-28 Mon
12:00~13:00
R1203
Nanase Harada
[ASIAA]
Connecting Galactic and extragalactic star formation - the case of astrochemistry
132018-05-16 Wed
12:00~13:00
R1203
Cheng, Jen-Chieh
[ASIAA]
TBD
142018-05-14 Mon
12:00~13:00
R1203
Ji-Jia Tang
[NTU]
The Physical Properties of an Exceptionally Blue QSO at z ∼ 6.6 and their Implication to the Early Growth of SMBH
Abstract

We explore the early growth of supermassive black holes (SMBHs) by using a near-infrared (NIR) spectrum of a recently discovered z = 6.621 QSO PSO J006+39 in three physical properties: (1) According to the standard thin disk model, the NIR (rest-frame FUV) spectrum of this QSO is dominated by the emission from the accretion disk. We found that the power-law slope of the continuum αλ of this QSO in NIR, −2.94 ± 0.03, is much bluer than the expected slope −1.5 from the standard thin disk model. We will discuss two possibilities to explain this unique slope: the black hole spin and the Comptonisation corona of the accretion disk. (2) The growth rate can be estimated by the Eddington ratio (Lbol/LEdd). We first estimated the SMBH mass by using the Mg ii line width and the rest frame luminosity L3000Å to be ∼ 108 M⊙ . Then we derived Eddington ratio Lbol/LEdd ∼ 1. (3) There are surprisingly many metal-rich QSOs found in the early universe, given the required time for metal formation. We present two probes to estimate the metallicity of this QSO. The Fe ii/Mg ii ratio is often used as an indicator for high-z QSOs because Fe metallicity requires a certain time to be enhanced by the Type-Ia supernovae. The detection of the faint He ii line in this QSO provides another path to measure the metallicity. We used N v/He ii ratio to estimate the metallicity by considering the blue FUV continuum in the photoionization calculation. We will discuss implications of these physical properties of this QSO about the growth of SMBHs in the early universe.

152018-05-07 Mon
12:00~13:00
R1203
Gabriel Torrealba
[ASIAA]
Satellites of Satellites: two dwarf galaxies brought by the LMC
162018-05-02 Wed
12:00~13:00
R1203
Ling, Hung-Hsu
[ASIAA]
Camera Construction and Imager Characterization for TAOS2
172018-04-30 Mon
12:00~13:00
R1203
Shan-Chang Lin
[NTU]
Self-consistent construction of virialized wave dark matter halos
182018-04-23 Mon
12:00~13:00
R1203
Teppei Okumura
[ASIAA]
Intrinsic alignments of emission line galaxies at z~1.4 with Subaru FMOS/FastSound survey
192018-04-18 Wed
12:00~13:00
R1203
Chang, Shu-Hao
[ASIAA]
GLT Report
202018-04-16 Mon
12:00~13:00
R1203
Kin-Wang Ng
[ASIOP]
The EDGES 21-cm absorption signal
212018-04-09 Mon
12:00~13:00
R1203
Howard Yee
[U. of Toronto]
The Quenching of Star Formation in Galaxy Clusters since z~1
Abstract

I will present an analysis of the quenching of star formation (SF) in galaxy clusters since z~1, based on a sample of 220 galaxy clusters from the SpARCS survey in the XMM-LSS and ELAIS-N1 fields, using the public data release from HSC-SSP and Sptizer SWIRE survey data in these fields. In particular, we examine the star-forming galaxy fraction (f_SF) as a function of redshift, galaxy stellar mass, and cluster-centric radius. I will also present some preliminary results on the SFR-stellar mass relation (the "main sequence") in the field and in clusters, using a combination of HSC and Spitzer SWIRE MIPS data, over the same redshift range.

222018-04-02 Mon
12:00~13:00
R1203
Ting-Hui Lee
[Western Kentucky University]
Galactic Archaeology with Planetary Nebulae
232018-03-26 Mon
12:00~13:00
R1203
Li-Hwai Lin
[ASIAA]
How to write a good ALMA proposal?
242018-03-21 Wed
12:00~13:00
R1203
Chang, Yen-Pin
[ASIAA]
Membrane Process on OMTs and Micro-lamps
252018-03-19 Mon
12:00~13:00
R1203
Jia-Wei Wang
[NTHU]
Multi-wavelength polarization observation toward the filamentary cloud IC5146
Abstract

Whether magnetic fields are important in the star formation is a fundamental question in astrophysics. The studies in past decades show that the role of magnetic fields in star formation is complicated and diverse, and that neither of the two extreme case theories (dominating or negligible magnetic fields) can fully explain the star formation activity. Hence, the detailed investigations of the role of magnetic fields in particular physical scale, density, and environments are necessary to reveal the full picture, which thus requires multi-wavelength observations to trace. In this talk, I would present our polarization observations in optical, infrared, and submillimeter wavelengths toward the filamentary clouds IC5146. I would first discuss how deep we can trace using each data set, and further show how the role of magnetic fields possibly change in different scale.

262018-03-12 Mon
12:15~13:15
R1203
Yong Tian
[NCU]
Mass Discrepancy-Acceleration Relation in Dark Matter Problem
Abstract

Mass discrepancy-acceleration relation (MDAR) is a relation in dark matter problem found in spiral galaxies. The mass ratio between observational mass divided by baryonic mass strongly related to baryonic acceleration (or observational acceleration) but unrelated to other physical quantities (ex, radius). Recently, McGaugh et al. 2016 (PRL117.201101) revealed a tight relation between observational acceleration and baryonic acceleration in 153 spiral galaxies from SPARC database which is consistent to the MDAR. It can well explain Tully-Fisher relation, deficient dark matter in ordinary elliptical galaxies, surface densities discrepancy etc. However, our work focus (Tian & Ko 2017) on elliptical galaxies in strong lensing such as Einstein rings. We found the MDAR in 57 elliptical lenses is consistent with spiral galaxies.

272018-03-07 Wed
12:10~13:00
R1203
Huang, Yen-Ru
[ASIAA]
The Progress of 1.5 THz HEB Mixer Based Receiver Cartridge Development
282018-03-05 Mon
12:15~13:15
R1203
Hsi-An Pan
[ASIAA]
Dependence of Global and Spatially-resolved SFR-M* Relations on Galaxy Properties
Abstract

The galaxy integrated star formation rate(SFR)-stellar mass(M∗) relation holds important information for understanding the star formation history and evolution of galaxies. Although the SFR-M∗ relation has been reported with a variety of different data sets, their appearance can vary significantly from one to another. In this work, we determine what controls the integrated and the spatially-resolved SFR-M* relation in both star-forming and quiescent galaxies by linking the spatially resolved SFR-M* relation with various galaxy properties such as stellar mass and bulge-to-total light ratio using MaNGA data (Mapping Nearby Galaxies at APO).

292018-02-26 Mon
12:15~13:15
R1203
Po-Sheng Ou
[NTU]
Understanding the Evolution and Environments of Supernova Remnants Through the Lx-Size Diagram
302018-02-12 Mon
12:00~13:00
R1203
Hans Zinnecker
[Deutsches SOFIA Institut (DSI), Univ. of Stuttgart]
Airborne Far-Infrared Astronomy with SOFIA
312018-02-07 Wed
12:00~13:00
R1203
Chang, Hsiao-Wen
[ASIAA]
Growth and Characterization of Epitaxial NbN Superconducting Films on SiC Substrate
322018-02-05 Mon
12:00~13:00
R1203
Tony Beasley
[NRAO]
ngVLA
332018-01-29 Mon
12:00~13:00
R1203
Yen-Ting Lin
[ASIAA]
A tale of two scaling relations
Abstract

I will talk about observational results that have puzzled me for the past 14 years, and show how the Hyper SuprimeCam Survey could help shed light on these.

342018-01-22 Mon
12:00~13:00
R1203
Li-Hsin Chen
[NTU]
Populating H2 and CO in galaxy simulation with dust evolution
352018-01-15 Mon
12:00~13:00
R1203
Hiroyuki Hirashita
[ASIAA]
New Taiwan-Russia Collaboration on Cosmic Dust
362018-01-10 Wed
12:00~13:00
R1203
Ho, Chin-Ting
[ASIAA]
Laser Tracker Ion
372018-01-08 Mon
12:00~13:00
R1203
Sung-Yung Hsiao
[ASIAA]
Recent Results from the ASIAA NanoSIMS
TEL: 886-2-3365-2200 FAX: 886-2-2367-7849
General: asiaa_replace2@_asiaa.sinica.edu.tw Media Request: epo_replace2@_asiaa.sinica.edu.tw
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