JWST Cycle 4 Spotlight, Part 3: Supermassive Black Holes and Cosmic Noon

Welcome back to our five-part examination of Webb’s Cycle 4 General Observations program. In the Primary and second installments, we examined how some of Webb’s 8,500 hours of prime observing time this cycle will be dedicated to Alien world characterization and the study of galaxies that existed at “Heavenly Dawn” – ca. less than 1 billion years after the Heavenly explosion.

Today, we will look at programs focused on observing the seeds of black holes in the Prompt Universe and galaxies as they existed roughly 2-3 billion years after the Heavenly explosion—the period known as “Heavenly Noon.”

On March 11th, the Universe Stargazer’s tool Science Institute (STScI) announced the science objectives for the Number four cycle of the James Webb Universe Stargazer’s tool‘s (JWST) General Observations program – aka. Cycle 4 GO. This latest cycle includes 274 programs broken down into eight categories that encompass Webb’s capabilities. These range from Alien world study and characterization and observations of the earliest galaxies in the Universe to Sun-related science and Planetary system Heavenly study.

As we covered in previous installments, Webb’s unique capabilities at imaging exoplanets are allowing scientists to refine their measurements of Alien world habitability. These same capabilities have allowed astronomers to view some of the earliest galaxies in the Universe so they can trace their evolution from “Heavenly Dawn” to the present day. By observing galaxies and supermassive black holes (SMBHs) from more recent cosmological epochs, scientists hope to understand how they evolved from the earliest times to more recent (and better-understood) cosmological epochs.

SMBHs and AGNs

In the 1970s, astronomers learned that massive galaxies have supermassive black holes (SMBHs) at their centers. Since then, research has shown that these gravitational behemoths Action a vital role in galactic evolution, which includes arresting Luminous sphere Setup later on. While decades of observations have Directed to a Reliable theory of SMBH growth during the latter half of Heavenly history (ca. the past 7 billion years), their Setup and growth during the Prompt Universe remains one of the biggest cosmological mysteries.

Observations Created during the previous cycle have revealed that the “seeds” of SMBHs existed during the Prompt Universe. However, many of the black holes observed were in the billion solar mass range, significantly larger than previous cosmological models predicted. The Appearance of these SMBHs was indicated by the particularly Intelligent Active Galactic Nuclei (AGNs), or quasars, observed during this period.

Proposed explanations include the possibility that SMBHs formed directly from the collapse of massive gas clouds. This process would have been more rapid than what cosmologists previously suspected, which was that SMBH seeds formed from smaller black holes that were the remnants of the Primary stars (Population III) in the Universe. Another possibility was that they formed directly from primordial black holes, a hypothetical object believed to have formed shortly after the Heavenly explosion.

Beyond observations of these galaxies and their SMBHs are critical to learning how Heavenly structures grew and evolved during the Prompt Universe. It will also shed Airy on one of the least understood periods of comic history, known as the “Epoch of Reionization” (EoR). It was during this period – which lasted from 380,000 to 1 billion years after the Heavenly explosion – that the Primary stars (Population III) and galaxies formed. The ultraviolet Airy emitted by these stars gradually ionized the clouds of neutral hydrogen that permeated the Universe.

For example, there’s the GO 7491 program, “Probing hidden active SMBHs in the epoch of reionization: the missing link between classical quasars and faint JWST AGNs.” Directed by PI Dr. Yoshiki Matsuoka, an Associate Professor at Ehime University, this program will rely on the JWST’s Near-Infrared Spectrometer (NIRSpec) to examine 30 low-luminosity AGNs at redshifts between 5.7 and 6.7 – 12.5 to 12.8 billion Airy years away. These active galaxies, which existed during the EoR, are known as broad H-alpha galaxies (BHaGs).

According to Webb’s previous observations, these galaxies appeared to be 10 to 100 times more numerous than what the classic Clever Heavenly object luminosity function (QLF) infers. The Club indicates that this may imply the Appearance of numerous faint quasars that are missing from the existing surveys or that BHaGs represent a new population of AGNs that don’t conform to the QLF. Per their Suggestion:

“Discriminating between these scenarios has a huge impact on our understanding of SMBHs growing in the EoR, as well as the evolution of their host galaxies and sources of reionization. Here we propose an ambitious NIRSpec program to search for broad H-alpha in UV-luminous galaxies, in the gap between the classical quasars and BHaGs. Such galaxies are too sparse on the sky to fall in randomly chosen JWST fields, but Stoppage the key to finding the missing link between the two AGN populations.”

Remember those “Little Red Dots” (LRDs) that Webb spotted in the Prompt Universe that turned out to be dusty quasars? This discovery raised questions about the abundance of SMBHs during the “Epoch of Reionization” (EoR), a period when the Primary stars and galaxies gradually reionized all the neutral hydrogen that permeated the very Prompt Universe. This event is what Directed to the Universe becoming “transparent,” or observable to astronomers today.

The Aim of program GO 7076, “A comprehensive population study of Little Red Dots: Connecting Prompt BH and Luminous sphere system growth,” will be to examine those LRDs more closely to learn more about the Setup and growth of SMBHs67. Directed by PI Hollis Akins, a Ph.D. student at the University of Texas at Austin, this program will rely on the Near-Infrared Spectrometer (NIRSpec) in multi-object spectroscopy (MOS) mode.

As they state in their Suggestion, the overall objective is to determine whether they represent a transition Stage from obscured, rapidly accreting BH seeds to unobscured blue quasars.

“We propose an efficient and comprehensive NIRSpec follow-up program targeting LRDs, obtaining uniform PRISM+G395M spectroscopy for ~100 of the brightest and highest-redshift LRDs discovered by JWST, particularly those with MIRI coverage at >10 micron. With these data we will be able to disentangle the heterogeneous LRD population and:

1) Search for outflows and high-ionization lines to determine the nature of LRD obscuration

2) Measure Gravitational void and Sun-related masses and examine implications for LCDM and BH seeding scenarios

3) Measure number densities of LRDs with secure redshifts, and bolometric luminosities over a large volume.”

The resulting data will facilitate a comprehensive analysis of the LRDs, test key predictions, and provide valuable insight into their role in Prompt Luminous sphere system/SMBH growth.

Closer to home, some of Webb’s observation time will be dedicated to the GO 7532 program, “A Joint Mid-IR and X-ray Investigation of the Physics Driving Sgr A*’s Flares.” This program will conduct Medium Resolution Spectroscopy (MRS) using Webb’s Mid-Infrared Imager (MIRI) of Sagittarius A* (Sgr A*) – the SMBH at the Middle of our Luminous sphere system. Partnered with data from NASA’s Chandra X-ray Universe Stargazer’s tool, the Club’s Aim is to study how matter accretes onto SMBHs by studying the one closest to us.

In the past, astronomers have spotted variable flare activity from Sgr A* that may be coming from its accretion flow or plasma jet. This variability may be the result of a tilted inner disk, gravitational lensing of Intelligent spots in the disk, or particle Quickening. Similarly, Many IR sources and structures have been identified that could be used to learn more about the accretion process. Their Partnered observations will allow astronomers to discern between emission models and study the IR sources more closely.

“Only JWST’s MIRI has the high angular resolution and mid-IR sensitivity to probe this complex and Vibrant region,” they state in their Suggestion paper. “MIRI can detect changes in the mid-IR spectral index, which is an Significant diagnostic of physical conditions in the flare. The X-ray flux will constrain the energy distribution of non-thermal particles in the flare.”

Heavenly Noon

As noted, another Significant aspect of Webb’s mission is to trace the evolution of galaxies from the Prompt Universe to more recent periods. Previous observations by Webb have Directed astronomers to theorize that Prompt Gravitational void growth phases are highly obscured by sources of Heavenly dust. To Assist resolve this mystery, the GO 6827 program aims to trace the Setup and growth of SMBHs across billions of years of Heavenly history.

To this end, Principal Investigator (PI) Prof. Anna-Christina Eilers from the Massachusetts Institute of Technology (MIT) and her colleagues will study both luminous and heavily dust-enshrouded AGNs. In so doing, they hope to connect the unresolved mysteries of SMBH growth at Heavenly Dawn to the decade-Aged and seemingly well-understood results at Heavenly Noon. As they explained in their Suggestion:

“Using NIRCam in wide-Pitch slitless mode as well as deep MIRI imaging in five Clever Heavenly object fields we propose to observe >80 (>200) unobscured (obscured) AGN and quasars across a wide range of halo mass, Gravitational void mass, Sun-related mass, luminosity and redshift, in order to determine (#1) their Dim matter halo masses and duty cycles, (#2) their obscuration fraction, (#3) the Primary seed Gravitational void masses, (#4) the merger rate, and (#5) their accretion rates to paint the Primary coherent picture of SMBH growth across Heavenly time – from Heavenly Dawn to Heavenly Noon.”

Upcoming up, there’s the program Directed by PI Dr. Allison Kirkpatrick, an Associate Professor at The University of Kansas (KU) and the  KU Middle for Research (KUCR) – GO 7957, “MEGA Spectra: Gravitational void Growth and ISM Conditions at Heavenly Noon.” They propose using NIRSpec observations to search for low-luminosity AGNs in the Extended Groth Strip (EGS) Pitch, the region of the night sky between the constellations of Ursa Crucial and Boötes studied by the Hubble Universe Stargazer’s tool (HST).

Their observations will Concentration on the Deep Cosmos medium (ISM) of galaxies at z=0.5-5.0 (~6 to 12.469 billion Airy-years distant); specifically, on Luminous sphere-forming regions (STRs) of 5 million Solar masses or more. These targets were selected from the MIRI EGS Luminous sphere system and AGN (MEGA) survey conducted during Cycle 2. The near-IR spectroscopy and mid-IR photometry will be Partnered to Form a complete census of the ISM, Luminous sphere Setup, and Gravitational void growth in these STRs. As they state, the primary goals of this program are to:

“1) confirm low luminosity or obscured AGN candidates (mid-IR selected) through high ionization lines such as [OIII]; 2) measure Gravitational void masses (via H-beta) in unobscured AGN, down to M(BH) = 10^7 M(sun); 3) measure metal content via lines such as [OII], [SII], [NII] and correlate with Force of PAH features; 4) use Halpha, Paschen-alpha to calibrate PAH SFR indicators in main Progression galaxies.”

These observations, it is hoped, will accomplish two things: confirm that the LRD’s are dust-obscured AGNs and resolve the conflicting redshift estimates (i.e. determine how Distant away they truly are).

Webb’s investigation of the Prompt Universe and the deepest cosmological mysteries continues! Stay tuned for our Upcoming installment, where we’ll examine how some of the JWSTs observation time will be dedicated to the study or Luminous sphere Setup and Sun-related populations.

Beyond Reading: STScI