OVERVIEW OF THE MASSIVE YOUNG STAR-FORMING COMPLEX STUDY IN INFRARED AND X-RAY (MYStIX) PROJECT

AbstractThe combination of spatial and spectral resolution allow us to use Chandra in the study regions of massive star formation which had been inaccessible even from the ground until the last decade. IRAC and MIPS data from Spitzer can be combined with the X–ray data to provide insight into the presence of a disk and the activity of the star. The total package allows us to better understand the evolution of the clusters. We have an ongoing program to study several young star forming clusters including distant clusters between 1-3 kpc which support O stars, RCW 38, NGC 281 and RCW 108 and well as clusters within a kpc including IRAS 20050+2720 and NGC 1579, which is a small cluster centered on the Be star LkHα101 and is of uncertain distance although the X-ray data help us refine the current distance estimates. Given the space constraints we only discuss RCW 108 below.

Download Full-text

A Chandra study of the morphological structure of the Wolf-Rayet dwarf starburst galaxy NGC 4214

Symposium - International Astronomical Union ◽

10.1017/s007418090021320x ◽

2003 ◽

Vol 212 ◽

pp. 720-721

Author(s):

Joanna M. Hartwell ◽

Ian R. Stevens ◽

David K. Strickland ◽

Timothy M. Heckman

Keyword(s):

Morphological Structure ◽

Young Star ◽

Starburst Galaxy ◽

X Ray ◽

Star Forming ◽

Star Forming Regions ◽

The Galaxy ◽

Starburst Regions

We present results from a Chandra X-ray observation of the dwarf starburst galaxy NGC 4214, a galaxy containing several young star forming regions. Starburst regions are known to be associated with diffuse X-ray emission, and in this case X-ray emission from the galaxy shows an interesting morphological structure with a bright X-ray ring of emission within the galaxy.

Download Full-text

Metallicity and X-ray luminosity variations in NGC 922

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3290 ◽

2020 ◽

Vol 500 (1) ◽

pp. 962-975

Author(s):

K Kouroumpatzakis ◽

A Zezas ◽

A Wolter ◽

A Fruscione ◽

K Anastasopoulou ◽

...

Keyword(s):

Star Formation ◽

Stellar Population ◽

Massive Stars ◽

Star Clusters ◽

Young Star ◽

X Ray ◽

Star Forming ◽

Star Forming Regions ◽

Main Driver ◽

Young Star Clusters

ABSTRACT We present a systematic study of the metallicity variations within the collisional ring galaxy NGC 922 based on long-slit optical spectroscopic observations. We find a metallicity difference between star-forming regions in the bulge and the ring, with metallicities ranging from almost solar to significantly sub-solar ($\rm {[12+\log (O/H)]\sim 8.2}$). We detect $\rm{He\,{\small I}}$ emission in all the studied regions of the bulge and the ring, indicating ionization from massive stars associated with recent (<10 Myr) star formation, in agreement with the presence of very young star clusters. We find an anticorrelation between the X-ray luminosity and metallicity of the sub-galactic regions of NGC 922. The different regions have similar stellar population ages, leaving metallicity as the main driver of the anticorrelation. The dependence of the X-ray emission of the different regions in NGC 922 on metallicity is in agreement with similar studies of the integrated X-ray output of galaxies and predictions from X-ray binary population models.

Download Full-text

VLBI Observations and NH3 Mapping of the Star-forming Region NGC2264

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313000264 ◽

2012 ◽

Vol 8 (S292) ◽

pp. 45-45 ◽

Cited By ~ 1

Author(s):

Tatsuya Kamezaki ◽

Kenji Imura ◽

Takumi Nagayama ◽

Toshihiro Omodaka ◽

Toshihiro Handa ◽

...

Keyword(s):

Proper Motion ◽

Young Star ◽

X Ray ◽

Star Forming ◽

Continuum Source ◽

Maser Spot ◽

Peculiar Motion ◽

Formation Efficiency ◽

Photometric Distance ◽

Water Maser

AbstractWe have measured the annual parallax of the water maser source associated with star forming region NGC2264 from observations with VLBI Exploration of Radio Astrometry (VERA). We detected masers at VLSR = 7.2 km s−1. We discussed its driving sources of detected maser spots. One of the maser spots was associated with a centimeter continuum source observed with VLA. Neither optical, infrared nor X-ray sources is catalogued near the spot. The other maser spot is located close to an X-ray source, although there is no optical or infrared counterpart. The proper motion of the former spot was (μα, μδ) = (23.91 ± 4.29, −29.81 ± 4.27) and the proper motion of latter spot was (μα, μδ) = (−0.96 ± 0.58, −6.05 ± 3.06). For the latter spot, the peculiar motion is ∼ 150 km s−1 and it has the high velocity and this may be a jet or an outflow from a young star. The observed parallax is 1.365 ± 0.098 mas, corresponding to the distance of 738+57−50 pc. This value is constant with the photometric distance of NGC2264 previously measured. The fitting result of the parallax is shown in figure 1. We also observed in NH3 (1,1), (2,2), (3,3) lines of NGC2264 with the Kashima 34m telescope. We estimated the star formation efficiency (SFE) of NGC2264 from the dense molecular mass of NH3 and the stellar mass calculated by Teixeira et al. (2012). The SFE is 9 – 12% which is consistent with previous results.

Download Full-text

Diffuse γ-ray emission toward the massive star-forming region, W40

Astronomy and Astrophysics ◽

10.1051/0004-6361/202037580 ◽

2020 ◽

Vol 639 ◽

pp. A80

Author(s):

Xiao-Na Sun ◽

Rui-Zhi Yang ◽

Yun-Feng Liang ◽

Fang-Kun Peng ◽

Hai-Ming Zhang ◽

...

Keyword(s):

Cosmic Ray ◽

High Energy ◽

Young Star ◽

Gas Content ◽

Large Area ◽

Stellar Cluster ◽

Production Region ◽

Star Forming ◽

Photon Index ◽

Young Star Clusters

We report the detection of high-energy γ-ray signal towards the young star-forming region, W40. Using 10-yr Pass 8 data from the Fermi Large Area Telescope (Fermi-LAT), we extracted an extended γ-ray excess region with a significance of ~18σ. The radiation has a spectrum with a photon index of 2.49 ± 0.01. The spatial correlation with the ionized gas content favors the hadronic origin of the γ-ray emission. The total cosmic-ray (CR) proton energy in the γ-ray production region is estimated to be the order of 1047 erg. However, this could be a small fraction of the total energy released in cosmic rays (CRs) by local accelerators, presumably by massive stars, over the lifetime of the system. If so, W40, together with earlier detections of γ-rays from Cygnus cocoon, Westerlund 1, Westerlund 2, NGC 3603, and 30 Dor C, supports the hypothesis that young star clusters are effective CR factories. The unique aspect of this result is that the γ-ray emission is detected, for the first time, from a stellar cluster itself, rather than from the surrounding “cocoons”.

Download Full-text

The role of AGN activity in the building up of the BCG at z ∼ 1.6

Proceedings of the International Astronomical Union ◽

10.1017/s1743921320003105 ◽

2019 ◽

Vol 15 (S356) ◽

pp. 280-284

Author(s):

Angela Bongiorno ◽

Andrea Travascio

Keyword(s):

Galaxy Cluster ◽

Cluster Galaxy ◽

X Ray ◽

Groups Of Galaxies ◽

Star Forming ◽

The Core ◽

The Galaxy ◽

Multi Wavelength

AbstractXDCPJ0044.0-2033 is one of the most massive galaxy cluster at z ∼1.6, for which a wealth of multi-wavelength photometric and spectroscopic data have been collected during the last years. I have reported on the properties of the galaxy members in the very central region (∼ 70kpc × 70kpc) of the cluster, derived through deep HST photometry, SINFONI and KMOS IFU spectroscopy, together with Chandra X-ray, ALMA and JVLA radio data.In the core of the cluster, we have identified two groups of galaxies (Complex A and Complex B), seven of them confirmed to be cluster members, with signatures of ongoing merging. These galaxies show perturbed morphologies and, three of them show signs of AGN activity. In particular, two of them, located at the center of each complex, have been found to host luminous, obscured and highly accreting AGN (λ = 0.4−0.6) exhibiting broad Hα line. Moreover, a third optically obscured type-2 AGN, has been discovered through BPT diagram in Complex A. The AGN at the center of Complex B is detected in X-ray while the other two, and their companions, are spatially related to radio emission. The three AGN provide one of the closest AGN triple at z > 1 revealed so far with a minimum (maximum) projected distance of 10 kpc (40 kpc). The discovery of multiple AGN activity in a highly star-forming region associated to the crowded core of a galaxy cluster at z ∼ 1.6, suggests that these processes have a key role in shaping the nascent Brightest Cluster Galaxy, observed at the center of local clusters. According to our data, all galaxies in the core of XDCPJ0044.0-2033 could form a BCG of M* ∼ 1012Mȯ hosting a BH of 2 × 108−109Mȯ, in a time scale of the order of 2.5 Gyrs.

Download Full-text

Tracing young SMBHs in the dusty distant universe – a Chandra view of DOGs

Proceedings of the International Astronomical Union ◽

10.1017/s1743921320004032 ◽

2020 ◽

Vol 15 (S359) ◽

pp. 17-21

Author(s):

Karín Menéndez-Delmestre ◽

Laurie Riguccini ◽

Ezequiel Treister

Keyword(s):

Star Formation ◽

Main Sequence ◽

Far Infrared ◽

Host Galaxy ◽

X Ray ◽

Star Forming ◽

Near Ir ◽

X Ray Imaging ◽

Combined Use ◽

Dusty Galaxies

AbstractThe coexistence of star formation and AGN activity has geared much attention to dusty galaxies at high redshifts, in the interest of understanding the origin of the Magorrian relation observed locally, where the mass of the stellar bulk in a galaxy appears to be tied to the mass of the underlying supermassive black hole. We exploit the combined use of far-infrared (IR) Herschel data and deep Chandra ˜160 ksec depth X-ray imaging of the COSMOS field to probe for AGN signatures in a large sample of >100 Dust-Obscured Galaxies (DOGs). Only a handful (˜20%) present individual X-ray detections pointing to the presence of significant AGN activity, while X-ray stacking analysis on the X-ray undetected DOGs points to a mix between AGN activity and star formation. Together, they are typically found on the main sequence of star-forming galaxies or below it, suggesting that they are either still undergoing significant build up of the stellar bulk or have started quenching. We find only ˜30% (6) Compton-thick AGN candidates (NH > 1024 cm–2), which is the same frequency found within other soft- and hard-X-ray selected AGN populations. This suggests that the large column densities responsible for the obscuration in Compton-thick AGNs must be nuclear and have little to do with the dust obscuration of the host galaxy. We find that DOGs identified to have an AGN share similar near-IR and mid-to-far-IR colors, independently of whether they are individually detected or not in the X-ray. The main difference between the X-ray detected and the X-ray undetected populations appears to be in their redshift distributions, with the X-ray undetected ones being typically found at larger distances. This strongly underlines the critical need for multiwavelength studies in order to obtain a more complete census of the obscured AGN population out to higher redshifts. For more details, we refer the reader to Riguccini et al. (2019).

Download Full-text

Double trouble: Gaia reveals (proto)planetary systems that may experience more than one dense star-forming environment

Monthly Notices of the Royal Astronomical Society Letters ◽

10.1093/mnrasl/slaa182 ◽

2020 ◽

Vol 501 (1) ◽

pp. L12-L17

Author(s):

Christina Schoettler ◽

Richard J Parker

Keyword(s):

Planetary Systems ◽

Young Star ◽

Young Stars ◽

Orion Nebula ◽

External Effects ◽

Star Forming ◽

Star Forming Regions ◽

Ejection Process ◽

Runaway Stars

ABSTRACT Planetary systems appear to form contemporaneously around young stars within young star-forming regions. Within these environments, the chances of survival, as well as the long-term evolution of these systems, are influenced by factors such as dynamical interactions with other stars and photoevaporation from massive stars. These interactions can also cause young stars to be ejected from their birth regions and become runaways. We present examples of such runaway stars in the vicinity of the Orion Nebula Cluster (ONC) found in Gaia DR2 data that have retained their discs during the ejection process. Once set on their path, these runaways usually do not encounter any other dense regions that could endanger the survival of their discs or young planetary systems. However, we show that it is possible for star–disc systems, presumably ejected from one dense star-forming region, to encounter a second dense region, in our case the ONC. While the interactions of the ejected star–disc systems in the second region are unlikely to be the same as in their birth region, a second encounter will increase the risk to the disc or planetary system from malign external effects.

Download Full-text