Connor Dickinson and friends*
UCSC Astronomy and Astrophysics
Figure 3: Spectra of SN 2023cj (red) compared to that of SN 2011bm (black) at early and late times. The labels to the right of the spectra are formatted as "Supernova, phase+[offset on the y-axis]"
Early-time Spectral Features*
Fe II triplet - 4924Å, 5018Å, 5169Å
Lack of He II line - 5876Å
Na I - 5956Å
Si II - 6150Å, 6355Å
H_alpha - 6562.8 Å
O I - 7774Å
Ca II triplet - 8498Å, 8542Å, 8662Å
Fe II - 8830Å
*[8][10]
Late-time Nebular Spectral Features*
Mg I - 4571Å
S I - 4589Å
Fe II octuplet - 5112Å, 5159Å, 5220Å, 5261Å, 5273Å, 5334Å, 5376Å
O I - 5577Å
O I doublet - 6300Å, 6363Å
Na I - 5956Å
Ca II doublet - 7291Å, 7323Å
O I - 7773Å
S I - 7722Å
Ca II triplet - 8498Å, 8542Å, 8662Å
C I - 8727Å
*[6]
The light curve of SN 2023cj ranging from a phase of 11 days pre-explosion to 201 days post-explosion
Peak magnitude at ~59961 MJD
Steep decline from peak for ~40 days followed by shallow drop-off
Steep decline slope of ~0.04 mag/day in r' band
Shallow decline slope of ~0.009 mag/day in r' band
Figure 4: Light curve of SN 2023cj with photometric data taken from YSE-PZ archives. Colors correspond to filters and shapes correspond to instruments.
Download and stack several Hubble Space Telescope images of NGC 5468 from before and after explosion
Identify stars in pre and post-explosion images using DAO Starfinder then match them together
Map post-explosion coordinates to pre-explosion image
Inspect pre-explosion image at the coordinates of the post-explosion star to attempt to find its progenitor star
Figure 2: Host galaxy of SN 2023cj in combined HST and JWST observations. Image credit NASA, ESA, CSA, STScI, Adam G. Riess (JHU, STScI)
Astrometry Between F350LP Pre-Explosion and F625W Post-Explosion Images
Figure 5: Pre and Post-explosion images of NGC 5468 with matched point sources between the two images marked in red, previously matched sources that were later removed with legendre fitting marked in yellow, and the supernova position marked in blue in both images. In the top-right corner of the pre-explosion image is a closeup of the supernova position in which the progenitor star of SN 2023cj should be seen if it is visible.
Results & Future Work
Results:
Did not find a progenitor star of 2023cj
Future Work:
Model the non-detection of the progenitor
Insert fake stars of various compositions and at various stages in their lifespan to attempt to match observations/supernova characteristics
Set hard limits on the depth of the drizzled images
As many may know, one of the demands of the UCSC Students for Justice in Palestine-led encampment was for the school to cut ties with "zionist" organizations including the Koret Foundation. The encampment at UCSC was the only UC to include this academic boycott into their demands. Regardless of my opinions on the matter, I felt it would be important to educate those who read this about the Koret Foundation's affiliations and allow them to form their own opinions on the matter. Below is a list of events following October 7th, 2023 along with a list of the Koret Foundation's main partnerships and what they believe/support based on my research.
Following the Hamas-led surprise attack on Southern Israel on October 7th, 2023, Israel declared itself in a state of war and began attacking Palestine relentlessly. As of May 22, there have been 35,709 reported fatalities, 79,990 reported injuries, and ~1.7 million persons internally displaced. Aside from the bombings and air strikes, the IDF has also been criticized for:
Inadequate or nonexistent warnings before Israeli airstrikes
As of May 10th, 254 aid workers and 492 health workers have been killed with some even being intentionally targeted such as workers of the World Central Kitchen (WCK)
Denial/delay of humanitarian aid to the Gaza strip (food, medical, water, sanitation, etc.)
As of March 27th, 212 out of 563 of school buildings in Gaza have received direct hits from the IDF. "No education is happening in Gaza at all for nearly six months," said the United Nations Relief and Works Agency for Palestine Refugees (UNRWA)
Refused Egyptian-Qatai-backed ceasefire proposal while simultaneously taking control of Rafah
The involvement of the Koret Foundation with Israel is multifaceted, as they fund and support a variety of organizations working in and with Israel. This is not meant to deface the Koret Foundation, it is only to educate and point out what they support. Below is a list of organizations this foundation is partnered with:
IsraAID - This is Israel's largest humanitarian aid organization and has used its reserves of volunteer medical professionals to provide emergency aid to 53 different countries.
After October 7th, IsraAID has regrouped in Israel and now works to evacuate citizens in southern Israel away from the Israel-Gaza border.
JCRC - The Jewish Community Relations Council works to mobilize Jewish voices in the Bay Area, countering antisemitism and other forms of hate. Some notable releases from this organization are:
A 2023 year-end survey concluding that antisemitism in the Bay Area has risen dramatically since October 7th, 2023
A statement before October 7th endorsing the Palestinian right to national self-determination as well as a statement 10 days after October 7th rejecting any form of hate towards all groups involved.
USC Shoah Foundation - An organization originally committed to recording the testimonies of Holocaust survivors that refocused their attention to victims of the Hamas attack on October 7th.
Tel Aviv University - set up psychological hotlines and sent out grants to reservists students
provide emergency housing and other aid and supplies through drives
provide student volunteers for projects supporting soldiers and citizens
Lev Echad (One Heart) - A civilian response organization that mobilizes volunteers in Israel and globally.
since October 7th, One Heart deployed 4 initial situation rooms
had 16 situation room headquarters by October 21st
50,000 volunteers to help:
evacuated families
farmers in fields
spouses of reservists and permanent soldiers
deliver support for families of hostages
support soldiers in IDF bases before entry into Gaza
Shalom Hartman Institute - Learning center for Jewish thought and education. Large collection of free educational materials.
"Our mission is to strengthen Jewish peoplehood, identity, and pluralism; to enhance the Jewish and democratic character of Israel; and to ensure that Judaism is a compelling force for good in the 21st century"
Museum of the Jewish People (ANU) - A museum dedicated to Jewish culture and education. They feature a wide variety of art and culture exhibits. Of particular note, ANU is responsible for:
An October 7th exhibit with works by 25 different artists "examining how Israeli culture reacts to the war"
Leads the "Bring Them Home" volunteer-based video campaign which aims to both raise awareness and money. They aim to bring home the hostages taken in the October 7th attack
Shalem College - staff, students, and alumni work together to aid in war efforts.
immediately after October 7th, set up command centers to help with immediate war needs and bring aid to student reservists and soldiers
Joined Jerusalem Operations Center, Chamal Yerushalmi, which is a call center that fields requests from soldiers, displaced citizens, reserve soldiers, and any others in need of aid during these times
Raised $4 million with Operation Iron Swords Relief Effort which provides soldiers with hot meals and supplies, houses displaced Israelies, and provides daycare services to children