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James Webb Space Telescope
JWST Science Corner

Recent JWST Science Highlights - High Redshift Galaxies

A 52 hours VLT/FORS2 spectrum of a bright z ~ 7 HUDF galaxy: no Ly-α emission

Why JWST is important:- The current limits of 8?10 m class telescopes in the spectroscopic characterization and redshift measurement of non-Ly-alpha emitters at 6.6 < z < 7.3 is shown. If z ~ 7 is a critical value above which the visibility of Ly-alpha lines decreases drastically, then future facilities are necessary to capture the UV continuum-break, the ultraviolet absorption lines, and/or optical nebular emission lines at 7 < z < 10. In particular, JWST will probe the typical Oxigen, Balmer lines, such as [OII]3727, H-beta, [OIII]4959-5007 up to z~9. These lines and/or the possible detection of other high ionization emission lines (e.g.,CiV1550, He1640, CIII]1909) will allow us to investigate the nature of the ionizing sources and indirectly their contribution to the reionization process. (click here for the abstract)

Reference: Eros Vanzella, INAF - Bologna Observatory, Co-authors:- Fontana A., Pentericci L., Castellano M., Grazian A., Giavalisco M., Nonino M., Cristiani S., Zamorani G., Vignali C., 2014,A&A,569,78

Vanzella Figure 5
Figure 5. 2014, A&A, 569, 78

A Simple Technique for Predicting High-Redshift Galaxy Evolution

Why JWST is important:-Motivation for constraining high-redshift galaxy formation. (click here for the abstract)

Reference: Peter Behroozi, STScI, Co-authors:- Joseph Silk, 2015, ApJ, 779, 32B

Behroozi Figure 15
Figure 15. 2015, ApJ, 779, 32B

Probing the Stellar Initial Mass Function with High-z Supernovae

Why JWST is important:-The first supernovae will soon be visible at the edge of the observable universe, revealing the birthplaces of Population III stars. Near-infrared missions such as JWST can detect the furthest supernova explosions, placing unprecedented constraints on the stellar initial mass function in the early Universe. (click here for the abstract)

Reference: Rafael S. de Souza, MTA Eötvös University, Co-authors:- E. E. O. Ishida, D. J. Whalen, J. L. Johnson and A. Ferrara, 2014, MNRAS, 442, 1640D

De Souza Figure 4
Figure 4. 2014, MNRAS, 442, 1640D

Superluminous Supernovae as Standardizable Candles and High-redshift Distance Probes

Why JWST is important:-The usefulness of Super Luminous Supernovae may be in redshift regimes beyond those possible for SN Ia, up to z=10. Hence, a space-based mission such as JWST will play a crucial role on finding these objects at high redshift. JWST will allow to populate the relation at high redshift and it will allow to investigate in possible dependencies of this objects with the host environment (click here for the abstract)

Reference: Cosimo Inserra, Queen's University Belfast, Co-authors:- Stephen Smartt, 2014, ApJ, 796, 87I

Inserra Figure 11
Figure 11. 2014, ApJ, 796, 87I

Early Galaxy Formation in Warm Dark Matter Cosmologies

Why JWST is important:-The standard Cold Dark Matter (CDM) paradigm has been hard pressed to explain observations of small-scale structure, prompting the need to invoke lighter Warm Dark Matter (WDM) particles. With its ultraviolet and infrared sensitivity, the JWST is ideally placed to measure stellar masses, and hence the redshift evolution of the stellar mass density in the first billion years of the Universe. It is such global quantities that will allow constraints on the mass of WDM particles, making the JWST an excellent WDM machine. (click here for the abstract)

Reference: Pratika Dayal, Institute for Astronomy, University of Edinburgh, Co-authors:- Andrei Mesinger & Fabio Pacucci, 2014, MNRAS, 1408, 1102D Submitted to MNRAS

Dayal Fig9
Figure 9. 2014, MNRAS, 1408, 1102D

High-redshift Galaxies and Low-mass Stars

Why JWST is important:-Distinguishing between faint cool sub-stellar objects (brown dwarfs) and very-high redshift galaxies (z~7 and above) with current instrumentation is difficult. JWST, with its array of wide and medium-band filters should be able to cleanly separate the two populations. (click here for the abstract)

Reference: Stephen Wilkins, University of Sussex, Co-authors:- Elizabeth Stanway, Malcolm Bremer, 2014, MNRAS, 439, 1038W

Wilkins Fig5
Figure 5. 2014, MNRAS, 439, 1038W

The Potential for Detecting Gamma-Ray Burst Afterglows from Population III Stars with the Next Generation of Infrared Telescopes.

Why JWST is important:- We model the flux density of GRBs from Pop III stars through JWST IR filters, and determine the length of time this flux density remains above JWST's sensitivity limits. (click here for the abstract)

Reference: Damien Macpherson, University of Western Australia, Co-authors:- David Coward, Marjan Zadnik, 2013, ApJ, 779, 73

Tanaka Fig4
Figure 4. 2013, ApJ, 779, 73

The Effect of Baryonic Streaming Motions on the Formation of the First Supermassive Black Holes

Why JWST is important:- Baryonic streaming (the relative motion of baryons against dark matter) can suppress the formation Population III stars at high redshifts. This effect may also suppress the number density of luminous quasars at z~11, which could be detected by JWST. (click here for the abstract)

Reference: Takamitsu L. Tanaka, Max Planck Institute for Astrophysics, Co-authors:- Miao Li, Zoltan Haiman, 2013MNRAS.435.3559T

Tanaka Fig4
Figure 4. 2013MNRAS.435.3559T

Simulating the Assembly of Galaxies at Redshifts z = 6 - 12

Why JWST is important:- We find that at redshifts z= 6-9, galaxies that are expected to be detected by the JWST contain about 1.5 times more stellar mass as compared to the larger and more luminous galaxies that have been observed as of date; the JWST will be instrumental in shedding light on the properties of such faint galaxies, in which most of the stellar mass is locked up at these high-redshifts. We also show that the JWST will be instrumental in pinning down the faint end slope of the UV LFs, shedding light on the physics driving star formation in these objects, as well as clarifying their contribution to the process of cosmic reionization. (click here for the abstract)

Reference: Pratika Dayal,Institute for Astronomy, University of Edinburgh U.K., Co-authors:- James S. Dunlop, Umberto Maio & Benedetta Ciardi, 2013MNRAS.434.1486D

Dayal Fig1
Figure 1. 2013MNRAS.434.1486D

Improving Dark Energy Constraints with High-redshift Type Ia Supernovae from CANDELS and CLASH

Why JWST is important:- We simulated a set of high redshift supernovae with the JWST redshift distribution and used them: (I) to study how they improve the constraints on dark energy parameters; (II) to check how they can help in disentangling peculiar intrinsic evolutionary supernovae features from cosmological (dark energy) ones. (click here for the abstract)

Reference: Vincenzo Salzano, University of the Basque Country, Co-authors:- Steven A. Rodney, Irene Sendra, Ruth Lazkoz, Adam G. Riess, Marc Postman, Tom Broadhurst, Dan Coe, 2013A&A.557A.64S

Salzano Fig6
Figure 6. 2013A&A.557A.64S

Supermassive Population III Supernovae and the Birth of the First Quasars

Why JWST is important:- JWST could perform detailed spectroscopic followup on these supermassive explosions if one were detected at z ~ 15 in an all-sky NIR survey. It may come across one itself during surveys of the first galaxies. (click here for the abstract)

Reference: Daniel Whalen,LANL, Co-authors:- Wesley Even, Joseph Smidt, Alexander Heger, K.-J. Chen, Chris Fryer, Massimo Stiavelli, Hao Xu and Candace Joggerst, 2013 ApJ, 778, 17

author Fig#
Figure 11. 2013 ApJ, 778, 17

The Spectral Evolution of the First Galaxies. II. Spectral Signatures of Lyman Continuum Leakage from Galaxies in the Reionization Epoch

Why JWST is important:- In order for galaxies to reionize the Universe at z > 6, some fraction of the hydrogen-ionizing (Lyman continuum) photons produced by hot stars in these objects must be able to escape into the intergalactic medium. Lyman continuum leakage can be detected at redshifts z < 4, but the opacity of the intergalactic medium precludes direct measurements of this kind at higher redshifts. Since the escape of ionizing photons regulates the impact of nebular emission on the spectra of galaxies, JWST/NIRSpec should nonetheless be able to indirectly probe Lyman continuum leakage well into the reionization epoch. (click here for the abstract)

Reference: Erik Zackrisson,Department of Astronomy, Stockholm University, Co-authors:- Akio K. Inoue, Hannes Jensen, 2013, ApJ, 777, 39

Zackrisson Fig7
Figure 7. 2013, ApJ, 777, 39

Detectability of the First Cosmic Explosions

Why JWST is important:- The emergence of the first generation of stars ended the cosmic dark ages and began the production of elements heavier than lithium. Ultimately giving rise to life on Earth. Near-infrared missions such as JWST have the potential to unravel the first supernovae explosions. Revealing the birthplaces of the first stars and providing unprecedented insights into cosmic evolution.Near-infrared missions such as JWST have the potential to unravel the first supernovae explosions. Revealing the birthplaces of the first stars and providing unprecedented insights into cosmic evolution. (click here for the abstract)

Reference: Rafael S. de Souza,Korea Astronomy and Space Science Institute, Co-authors:- Emille Ishida, Jarrett Johnson, Daniel Whalen, Andrei Mesinger, 2013, MNRAS, 436, 1555

de Souza fig5
Figure 5. 2013, MNRAS, 436, 1555

Formation of Primordial Supermassive Stars by Rapid Mass Accretion

Why JWST is important:- JWST should be able to detect rapidly accreting (and greatly bloating) supermassive stars, which could be very embryos of the supermassive black holes (SMBHs) observed in the early universe. Theoretical work has predicted that this should happen as a mode of the Pop III star formation. JWST can verify this scenario and examine seeding of the first SMBHs. (click here for the abstract)

Reference: Takashi Hosokawa,The University of Tokyo, Co-authors:- Harold W. Yorke, Kohei Inayoshi, Kazuyuki Omukai, Naoki Yoshida, 2013, ApJ, 778, 178

author fig#
Figure 12. 2013ApJ...778..178H

Gas Infall into Atomic Cooling Haloes: On the Formation of Protogalactic Disks and Supermassive Black Holes at z>10

Why JWST is important:- The possibility that the James Web Space Telescope(JWST) can observe the first galaxies, located in haloes >~10 times more massive than those hosting the first PopIII stars, is an exciting motivation to study the so-called atomic cooling haloes (i. e. DM haloes with a virial temperature Tvir>~1E4K). (click here for the abstract)

Reference: Joaquin Prieto, Bulgarian Academy of Science, Co-authors:- Raul Jimenez, Zoltan Haiman, 2013MNRAS, 436, 2301